Edioth, chap. 2, mish. 10.
Plagues come upon those that are proud, as was the case with Uzziah (2 Chron. xxvi. 16), "But when he was strong (proud), his heart was lifted up to destruction." When the leprosy rose up in his forehead, the Temple was cleft asunder twelve miles either way.
Avoth d'Rab. Nathan, chap. 9.
This hyperbole is evidently a mere fiction joined on to a truth for the purpose of frightening the proud into humility. The end sanctifieth the means, as we well know from other instances recorded in the Talmud.
Those who mourn for deceased relatives are prohibited from entering a tavern for thirty days, but those who mourn for either father or mother must not do so for twelve months.
Semachoth, chap. 9.
A creature that has no bones in his body does not live more than twelve months.
Chullin, fol. 58, col. 1.
The Alexandrians asked Rabbi Joshua twelve questions; three related to matters of wisdom, three to matters of legend, three were frivolous, and three were of a worldly nature—viz, how to grow wise, how to become rich, and how to ensure a family of boys.
Niddah, fol. 69, col. 2.