Alef opens the alphabet and has the value one. Sefer Yetzirah places it among the letters formed in the throat, with Chet, Heh and Ayin. Its name is commented on by the Midrash: Rabbi Hoshaya asks why it is called Alef, and answers that it agrees with elef, a thousand, as in the verse "the word He commanded for a thousand generations."
In Sefer Yetzirah, Alef is the first of the three mothers, Emesh. Mem is silent, Shin hisses, and Alef, which is air and breath, ruach, "decides between them." The book compares it to the tongue of the scale, the law that decides between the pan of merit and the pan of guilt. G-d "made the letter Alef reign over breath and bound a crown to it," and through it formed air in the world, the temperate season in the year and the torso, geviyah, in the body of man and woman.
In tractate Shabbat, the Sages tell Rabbi Yehoshua ben Levi that children came to the house of study and said things that had not been said even in the days of Joshua son of Nun. Their reading begins thus: "Alef Bet, alef binah," learn wisdom. The name of the letter becomes a verb, alef, "learn," and the name of the next one gives binah, understanding. The first lesson of the alphabet is an invitation to study.
The Midrash Bereshit Rabbah asks why the world was created through a Bet, that of bereshit, and not through Alef. Rabbi Elazar bar Hanina, in the name of Rabbi Acha, relates that for twenty-six generations Alef complained before the throne of the Holy One, blessed be He: "I am the first of the letters, and You did not create Your world through me." G-d answered that the world and all it contains were created only by the merit of the Torah, and added: "Tomorrow I come to give the Torah at Sinai, and I will open only with you," anokhi, "I am the Lord your G-d." Sefer HaBahir says for its part that Alef stands at the head because it preceded everything, even the Torah. The Alphabet of Rabbi Akiva reads the three letters of the name as initials: emet, lamed, pikha, "teach your mouth truth," to merit the life of this world, and in the reverse order to merit the world to come.
Alef has the value one, stands at the beginning and is pronounced like a breath. The sources give it two roles: in Sefer Yetzirah, it is the air that arbitrates between water and fire; in the Midrash, it opens the word of Sinai rather than creation. And the children of the house of study draw from it the first instruction of the alphabet: learn.