How is it proved that mourning should be kept up for seven days? It is
written (Amos viii. 10), "I will turn your feasts into mourning," and
these in many cases lasted seven days.
_Moed Katon_, fol 20, col. 1.
Rav Chisda said there are seven kinds of gold:--Gold, good gold, the
gold of Ophir, purified gold, beaten gold, shut-up gold, and gold of
THE TALMUD, _Yoma_ fol. 44, col. 2.