Rabbi Levi says the realization of a good dream may be hopefully
expected for twenty-two years; for it is written (Gen. xxxvii. 2),
"These are the generations of Jacob, Joseph being seventeen years old
when he had the dreams." And it is written also (Gen. xli. 46), "And
Joseph was thirty years old when he stood before Pharaoh," etc. From
seventeen to thirty are thirteen, to which add the seven years of plenty
and the two years of famine, which make the sum total of twenty-two.
THE TALMUD, _Berachoth_, fol. 55, col. 2.