The Mitzvah of Brit Milah is practiced today in many forms very different from the traditional practice. Many of these methods are simply not acceptable, according to Halacha -- Jewish Law, and render a Brit Milah unkosher, that is, invalid. Thus, for many Jews, this vital Mitzvah still remains to done.

There is general, widespread agreement that the glans must be completely revealed -- the word 'Milah' refers to 'revealing.'
However, some uninformed Mohalim have begun to neglect the 'Periah' and 'Metzitza' that make the Mitzvah complete. In fact, this is not a new phenomenon. It should come as no surprise that the Talmud and its sages were not silent about these two great omissions, as you'll see.

1. I have received the tradition that the Periah must be done with the fingernails only and anyone who does the Periah without tearing (With the fingernails) he is doing the wrong thing (Rabbenu Yaakov ha Gozer, one of the Baale Tosfot, 19)
   
   
2. Therefore we cut the foreskin and discard it and afterwards we tear the skin (PERIAH) and we do not cut it or discard it like we do with foreskin because this skin is holy. (Ha An ha Kadosh and his student Rabbi Chayim Vital)
   
   
3. The Mitzvah of Brit Milah is to cut the Orlah and the Periah meaning that the Mitzvah is divided in two parts and this is proper The first one [ORLAH] we cut and the second one we tear and pull back [PERIAH]. (Rabbi Moshe Cordobero on the Tikkune Zohar Part 3, page 232)
   
   
4. In the Mitzvah of Milah three things have to be performed: Milah, Periah and Metzitza. Milah is the cutting of the foreskin, the Periah is to tear the fine skin with the fingernail and there is no need to cut it but one has to incorporate it into the skin, and the Metzitza is the impure blood. (Ha Gaon Rabbi Chayim ben Attar ztk'l, Or ha Chayim Parashat Tazria)
   
   
5. Given that I have seen those who claim, G-d forbid, that the Mitzvah of Periah that we have received all of us Jews, is not necessary, but all we need to do is to uncover the crown, but this is not so and on the contrary our Sages said: "We tear the fine skin with the fingernails and pull it back to this side and that side and obviously we have to tear the skin with the fingernail" (Peri ha Adama on the Rambam, Hilchot Milah)
   
   
6. Also on grown ups the Mitzvah of Periah is required and this a Halacha given to Moshe on Mount Sinai (Halacha le Moshe mi Sinai) that even after having exposed the crown we need to "Tear the fine skin of the Periah precisely" (Yam shel Shelomo, Yevamot Mishkan Betzalel on the Recanati Siman 595)
   
   
7. According to the ways of truth, it is proper to perform the Mitzvah of Periah with the fingernail so that the nail which is the Kelipah may come and cut the ORLAH and annul its strength. (Zecher David Maamar A, 21, See also Yalkut Reuveni)
   
   
8. If the skin of the Periah was already cut then it's impossible to affix the skin and do the Periah with the fingernail, but if one has the possibility it is obviously proper to perform the Periah with the fingernail an this is very simple (Sheelot u Teshuvot Zerah Emet from the Gaon Rabbi Yishamel ha Cohen mi Modena, Yoreh Deah Siman 264, Siman 132)
   
   
9. The Periah should only be done with the fingernails and thus wrote the Rambam and the Sefer Mitzvot Gedolot and the Or Zarua and it is also brought in a few Midrashim from our Holy Sages Z"L. And don't look at those who think themselves to be sages of the Torah and that try to annul any of the traditions and customs of Israel for all of them are based on Mountains of Holiness [Yesodatan be Harere Kodesh] (Zocher ha Berit Siman 11, letter 16)
   
   
10. The ORLAH is made up of two Kelipot [husks] and they are ESAV and YISHMAEL and therefore we need cutting and tearing. First we need to cut the foreskin (ORLAH) completely, and then the Kelipat of Yishmael is Kelipat Nogah and it is not proper to destroy it. (Morenu ha Rav Reb Nachman ZTK"L sefer Berit Shalom)
    
    
11. In the ORLAH itself there are three Kelipot and they must be eliminated but the Periah we need not cut and eliminate but to separate and that it be integrated into the skin (The Vilna Gaon ZTK"L, Hagahot on Tikkune Zohar Tikkun 37)
    
    
12. And who was able to stand and listen to the secrets of Hashem, and He said to cut the foreskin [ORLAH] and He commanded us through a HALACHA LE MOSHE MISINAI to tear the very thin skin and that we do not need to cut this fine skin but only to tear it [PERIAH]. (Maharam Shick ZTK"L Sheelot u Teshuvot Yore Deah Siman 245)
    
    
13. The RAMBAM wrote that we perform the Periah with the fingernail and that the source for this practice is in the AGADAH, and we must say that this is a tradition from the Rabbanim. (Rab Vasserman ZTK"L, Kobetz Shiurim Yevamot 64, 8)
    
    
14. The manner in which the Periah is performed with the fingernails is well known and accepted through all the communities of Israel and it is obvious that we received the tradition from Moshe Rabbenu and the Mishna we also received from Moshe Rabbenu (Sheelot u Tshuvot Binyan Tzion Siman 85, Rab Etlinger ZTK"L)
    
    
15. G-d forbid that we change our traditions therefore we must perform the Periah with the fingernails (Koret ha Brit Hilchot Milah Siman 264)
    
    
16. The verse where it is written CHARVOT TZURIM: (At that time the Lord said to Joshua, Make sharp knives, and circumcise again the people of Israel a second time - Yehoshua 5:2) refers to the dripping of the blood of the Brit, and the Periah was done with the fingernail and this is clear (Ha Gratz Chayot 60)
    
    
17. The one who circumcises [The Mohel] will do two Milahs: The ORLAH which one needs to remove completely and this is done through cutting it, and then He must do the Periah that one has to tear and pull back the bad into the good (The Gaon and Holy Baal Sfat Emet Parashat Ki Tetze 656)
    
    
18. The ORLAH is the Kelipah [husk] and we need to cut it and put it away in the dust, but the second thin ORLAH is the secret of the nails and this Kelipah stays there just like the Rasha crowns the Tzaddik (Beit ha Levi 13)
    
    
19. In the Mitzvah of Milah there are two things the cut with an utensil and the tearing with the hand And the seed of Israel by performing the Periah with the hand gains control of Yishmael (Kedushat Levi, Lech lecha)
    
    
20. The reason for the Mitzvah that we were commanded to cut the thick skin [foreskin] which comes from the 3 Kelipot that are completely evil, and we need to cut this skin and to annul it completely, and the fine skin which is composed of Kedusha and Kelipa, we were commanded to tear and to integrate it to the crown (Derech Pikudecha, Milah, 10)
    
    
21. The Torah commanded us to cut the thick skin and after this cutting is concluded, the Periah should be performed with the fingernail, and there are some who perform the Periah without using the fingernail but use a utensil instead. This is obvious the practice of fools and we should not introduce new things like this one and we should do what our fathers did, and we haven't seen such thing done in our land. (Aruch ha Shulchan Yoreh Deah Siman 264, saif 16)
    
    
22. The influence of forces of evil are stronger on the nails and therefore the Kelipah comes and brakes the ORLAH to annul its force and G-d forbid that we should change our traditions to tear the skin with the fingernails (Yaabetz, Secret of the Tzipporen Male and the Tzipporen Chasser)
    
    
23. Great sages have already forbidden to tear the skin [Periah] with scissors and this causes the child great pain as it takes a long time. And the Periah should be done only with the fingernails. (The Gaon ADMOR mi Munkatch ZTK"L, letter Shalom Siman 260)
    
    
24. One can argue that the use of sharp knives by the Jews in the times of Yehoshua was required because it is impossible to perform the Periah with the fingernails in adults and then the Periah is Kosher also with an utensil but when it is possible to perform the Periah with the fingernail then it is forbidden to do so with an utensil and the Periah is not Kosher with an utensil (The Gaon Rabbi Chaim Ozer ZTK"L Sheelot u Teshuvot Achiezer Chelek Gimmel Siman 65)
    
    
25. The tearing written by the Rambam consists of tearing with the fingernail and it is Halacha Le Moshe Mi Sinai and if he didn't tear he didn't accomplish the Mitzvah and he annulled the customs of the people of Salonica (Mahari Dantzig, Sheelot u Teshuvot Mahari Yore Deah Siman 19)
    
    
26. Regarding the law of Periah without using the fingernail, G-d forbid for any Mohel to change the tradition we have received, and I see in this a great brake of Torah fences and if this is done by someone on purpose [BEMEZID] the Bet Din should relieve him of his occupation as a Mohel (Sheelot u Tshuvot Or ha Meir Siman 58, Rabbi Shapiro mi Lublin ZTK"L)
    
    
27. Those who innovate and perform the Periah with an utensil and not with the fingernails as explained by the Rambam and the Tur Shulchan Aruch and the Poskim, these innovators have already been rebuked in the sefer Binyan Tzion (Sheelot U tshuvot Chelkat Yaakov, Chelek 3, siman 85)
    
    
28. The one who cuts the skin of the Periah together with the foreskin [ORLAH] in Shabbat, has to worry for he may be transgressing the prohibition of destroying in Shabbat (Sheelot u Tshuvot Emek Halacha)
    
    
29. Regarding the new practices done by some Mohels that they cut the two skins together and they do not perform the Periah with the fingernails, It is obvious that the Periah has to be performed with the fingernail and it is a tradition we have received from our fathers all the way back to Moshe Rabbenu just like the tradition we have regarding the Etrog, and I worry about the Mohel if his soul belongs to those of Amalek may his name be blotted out and to my knowledge he should be warned that if he continues to do this, that he be disqualified from being a witness just like one who hits a fellow Jew. (Rabbi Greenwald, Av bet Din Keh. Arugat ha Bosem, Sheelot utshuvot Migdelot Merkahim Sim 81)
    
    
30. It is forbidden to change the Mitzvah of Milah in any respect, and G-d Forbid that someone should annul the Mitzvah of Periah with the fingernail. (Rabbi Israel Alter, Admor mi Gur ZTK"L)
    
    
31. Ha Rav Ha Gaon Rav Aronfeld ZTK"L Av Bet Din Mattersdorf never wanted to be a Sandak in a place where the Mohel would not perform the Periah with his fingernails.
    
    
32. It is quite obvious that it is forbidden to introduce any changes in the Milah even if they are small, and even more so not to cut the skin of the Periah and there may be the prohibition of destruction here (The ADMOR mi Papa ZTK"L)
    
    
33. He who cuts the skin of the Periah together with the foreskin in one shot has annulled the Mitzvah of Periah and if he did this in Shabbat he is liable to the penalty of Karet. (Ha Gaon Rav Yudelbitz ZTK"L Sheelot u tshuvot Bet Av Chamishia, Siman 276, 277)
    
    
34. Any Mohel who annuls and disregards the customs and traditions we have received from our forefathers as regards to the Mitzvah of Milah, Periah and Metzitza, has to be removed from his post. (Sheelot uTshuvot Levushe Mordechai from Rav Mordechai Epstein mi Slobodka)
    
    
35. He who cuts the foreskin [ORLAH] together with the skin of the Periah and does not tear the skin of the Periah with the fingernails, it is a great removal of the Yoke of the Torah and who has permitted them to change the Mitzvah of Milah and depart from the ways and customs we have received from our fathers? (Ha ray Ha Gaon Rav Kanievsky SHLITA The Steipler)
    
    
36. G-d forbid that we should change and cut the skin of the Periah and to annul the tearing with the fingernail, and it is clear that he who cuts the Periah is liable for the transgression of destruction and in Shabbat he is liable to the penalty of death by stoning, and there is no doubt regarding this and G-d forbid that we should change the least in the way it is supposed to be performed. (Ha Gaon ha Kadosh Rabbi Yosef Shalom Eliashev SHLITA one of the Poskim of our generation in Jerusalem)
    
    
37. The Mitzvah of Milah consists in cutting the ORLAH first and afterwards to tear the skin of the Periah that is underneath, and he who cuts the two skins has annulled the Mitzvah of Periah, and the Mohel is liable for having destroyed and in Shabbat he is liable to the penalty of Karet (Ha Gaon HA Gadol Rav Menashe Klein SHLITA, Sheelot utshuvot Mishne Halachot, and look further in his book MAL VE LO PARA)
    
    
38. Regarding the innovators who resolved to perform the Mitzvah of Milah and the Mitzvah of Periah in a new way, it is clear to me that it is forbidden to change from the form in which a Mitzvah is performed from that which we received from Moshe Rabbenu from generation to generation, and whoever changes is almost considered as if he didn't accomplish the Mitzvah, that even according to the Torah he did not accomplish the Mitzvah for he deviated from the form in which the Mitzvah ought to be performed for he has not cut first with the knife and afterwards hasn't torn the skin with the fingernails (Ha Gaon Ha Gadol Rav Shmuel Vosner SHLITA, Sheelot and Teshuvot Shevet ha Levi Yore Deah Siman 132)
    

• R. Shimon said: 'A man who begets a son becomes linked with the Shechinah, which is the gateway to all the heavenly doors, the door which is linked with the Holy Name. Also, the blood which flows from the child is preserved before the Almighty, and when punishment impends over the world, G-d looks at that blood and delivers the world. We have learned that through that blood the world is based on loving kindness (Chessed), and all worlds are established.'
  
  
• So R. Shimon expounded the words- "If not for my Covenant day and night, etc." (Jer. 33, 25), saying:
  'There are two Crowns linked together, they being the gateway to all other Crowns; one is Justice and the other is Mercy, one male and one female, one white and one red. This Covenant takes hold of both of them, loving kindness and judgment, day and night. Hence it is called "day and night", because it takes hold on both. Thus he who is able to keep this Covenant without fail and offends not against it all his days takes hold of day and night and is rewarded in two worlds, in this world and the world to come. (The Holy Zohar Vayikra 14a)
  
  
• The Sages say, Great is Brit Milah, for were it not for Brit
  Milah, heaven and earth would not have endured, as it is
  written, "Were it not for My Covenant, I would not have
  created day and night, the laws of heaven and earth.
  (Yirmiyahu 33:25)
  (Talmud Shabbat 137b)