Rabbi Yehuda ben Teima רבי יהודה בן תימא

Rabbi Yehuda ben Teima was a Tanna of the last generation of whom almost nothing is known except one line that everyone knows: "Be bold as a leopard, light as an eagle, swift as a deer and strong as a lion to do the will of your Father in Heaven" (Avot 5:20). The Rema opens the Shulchan Aruch with this line: the code by which the whole Jewish world lives begins there—because before any particular law stands the question of the character a person brings to it.

"Bold as a leopard" is above all against shame: do not be embarrassed before scoffers when you serve. Next in Avot comes the ladder of ages—five years for Scripture, ten for Mishnah, thirteen for the commandments, eighteen for the wedding canopy—and tradition attaches it to him as well.

The sources give no years of life; the window of activity is set by generation, following Aharon Hyman's Toldot Tannaim ve-Amoraim.