One letter out of place in the Torah destroys the entire universe

"Rabbi Ishmael said to me, ‘My son, what is your occupation?’ I told him, ‘I am a scribe’, and he said to me, ‘Be meticulous in your work, for your occupation is a sacred one; should you perchance omit or add one single letter [in preparing a Torah scroll], you would thereby destroy all the universe’."

-- Talmud Bavli, tractate Eruvin 13a



To better understand this quotation from the Talmud, please read this page on the rigors of preparing a Torah scroll:



Making a Torah Scroll - How is it made?

Some highlights:

• There are 304,805 letters in a Torah Scroll.
• Each page has 42 lines.
• The Torah Scroll must be written by a specially trained pious scribe called a sofer.
• It takes about a year to write an entire Torah Scroll.
• Even a single missing or misshapen letter invalidates the entire Sefer Torah. [!!!]
 

The Talmud on the Creation of the World with the Letters Yod and Heh

"R. Judah the patriarch asked R. Ammi: What is the meaning of the verse, 'Trust ye in the Lord for ever; for in Yah the Lord is an everlasting rock?' He replied: It implies that if one puts his trust in the Holy One, blessed be He, behold He is unto him as a refuge in this world and in the world to come. This, retorted the other, was my difficulty: why does the verse say 'in Yah' and not 'Yah?' The reason is as was expounded by R. Judah ben R. Ila'i: Yah, he said, refers to the two worlds which the Holy One, blessed be He, created, one with the letter heh and the other with the letter yod. Yet I do not know whether the future world was created with the yod and this world with the heh or this world with the yod and the future world with the heh; but since it is written, 'These are the generations of the heaven and of the earth when they were created' read not 'be-hibare'am' 'when they were created', but 'be-he bera'am', 'He created them with the heh'; hence I may say that this world was created with the heh and the future world with the yod."

-- Talmud Bavli, tractate Menachot 29b