Kuf is the nineteenth letter and its value is one hundred. It has no final form. Its shape has a peculiarity the Talmud comments on: its leg is suspended and does not touch the roof of the letter.
In Sefer Yetzirah, kuf is the last of the twelve simple letters, placed at the twelve diagonal edges of space, "the arms of the world," with twelve foundations, from sight to sleep. For kuf the book writes: "He made the letter kuf king, He bound a crown to it," and formed through it the Fish in the world, the month of Adar in the year and the gizzard, korkeban, in the soul. The book adds that the simples are arranged "like a battle," one facing the other. In the classification of sounds, kuf belongs to the letters of the palate, gimel, yod, kaf, kuf.
The Talmud reports the reading of the alphabet that children once gave in the study hall, which the Sages came to relate to Rabbi Yehoshua ben Levi. "Kuf: kadosh, holy; reish: rasha, wicked." Why is the face of the kuf turned away from the reish? The Holy One, blessed be He, said: I cannot look at the wicked. Why is the crown of the kuf turned toward the reish? The Holy One, blessed be He, said: if he returns, I bind for him a crown like Mine. Why is the leg of the kuf suspended? So that, if he returns, he may enter through there. The Gemara asks: let him enter through the opening at the bottom! And it answers with the teaching of Reish Lakish: one who comes to defile himself, they open for him; one who comes to purify himself, they help him.
The Alphabet of Rabbi Akiva gives two texts. In the account of the letters presenting themselves before the Holy One, blessed be He, before creation, kuf pleads: through me the threefold holiness will be proclaimed before You, "Holy, holy, holy is the L-rd of hosts." The answer is no: through you curses, kelalot, will come upon the generation of the flood, as Job says, "he is swift upon the face of the waters, their portion is cursed on the earth." In the other version, kuf is Moses, father of the sages and the prophets, who unfolded before Pharaoh every word of wisdom and understanding in seventy languages.
The sources read kuf as holiness. The Talmud draws a precise teaching from it: holiness does not look evil in the face, but it keeps its crown turned toward the one who has fallen, and it leaves an opening above, a narrow one, through which he can return. Whoever wishes to purify himself, says Reish Lakish, does not enter alone: he is helped.
