Menachos Daf 29 מנחוס דַף 29

The Mishnah taught that even a single letter is מעכב in a מזוזה, and since even the קוצה של יוד – point of the [letter] yud is obviously מעכב, the Gemara explains it teaches Rav’s ruling: כל אות שאין גויל מוקף לה מארבע רוחותיה פסולה – any letter which is not surrounded by parchment on its four sides is invalid. Rav Yehudah said: ניקב תוכו של ה"י כשר – if the inside of a hei (the blank parchment inside) is punctured, it is valid, but if יריכו – its leg is punctured, it is invalid. This means that it is only valid if there was enough left of the leg כשיעור אות קטנה – like the size of the smallest letter (a yud). Rebbe Abba ruled this way for his father-in-law, who had tefillin in which the "ה" of "העם" was split by a hole. Rami bar Tamrei had tefillin in which the leg of the vav of "ויהרג" – and He killed was split by a hole, and it appeared somewhat like a yud. Rebbe Zeira ruled: זיל אייתי ינוקא דלא חכים ולא טפש – Go bring a child who is neither clever (who would figure out the correct reading) nor foolish (who can only read perfectly written letters); if he reads it correctly, it is valid, but if not, then it reads as "ייהרג" – He shall be killed, and is invalid.

When Moshe went up to שמים, he saw Hashem sitting and tying תגין – crowns to letters, and asked who prevents Hashem from giving the Torah as is. Hashem said, “There is a man destined to live after many generations, named Akiva ben Yosef, שעתיד לדרוש על כל קוץ וקוץ תילין תילין של הלכות – who is destined to darshen piles and piles of halachos from each and every point. Moshe asked to see him, and, upon observing Rebbe Akiva’s class, he could not understand what they were saying and became weakened. Rebbe Akiva’s students asked him for his source, which he said was a הלכה למשה מסיני, and Moshe’s mind was relieved. Moshe said: רבונו של עולם יש לך אדם כזה ואתה נותן תורה על ידי – “Master of the World, You have a person like this and You give the Torah through me?!” Hashem replied: שתוק כך עלה במחשבה לפני – “Be silent; thus has arisen in thought before Me, and it is not for you to understand.” Moshe asked to see Rebbe Akiva’s reward, and Hashem showed him Rebbe Akiva’s flesh being sold in the market. Moshe said: רבש"ע זו תורה וזו שכרה – “Master of the World! This is the Torah and this is its reward?!” Hashem again replied: שתוק כך עלה במחשבה לפני.

The passuk says "כי בי-ה ה' צור עולמים" – for in G-d, Hashem, is the strength of the worlds, and Rebbe Yehudah bar Rebbe Il’ai darshened that it is written "בי-ה" with a beis to refer to the two worlds which Hashem created with a yud and a hei. עולם הזה was created with a hei, מפני שדומה לאכסדרה  - because its design is similar to a pavilion (i.e., open underneath), שכל הרוצה לצאת יצא – that anyone who wants to leave righteousness and engage in wickedness has the free will to do so. The left leg of the hei is suspended, דאי הדר בתשובה מעיילי ליה – so that if he returns in repentance, they can bring him back through the opening. The Gemara asks why he cannot re-enter from where he left, and explains: לא מסתייעא מילתא – it will not be successful, as Reish Lakish taught: בא לטהר מסייעין אותו – if one comes to purify himself, he is assisted from above, בא לטמא פותחין לו – but if he comes to defile himself, they provide him an opening to do so. The hei has a תג, because Hashem says: אם חוזר [בו] אני קושר לו [כתר] – if he repents, I will fasten for a crown to [his head].