When God revealed Himself upon Mount Sinai, all Israel sang a song of jubilation to the Lord, for their faith in God was on this occasion without bounds and unexampled, except possibly at the time of the Messiah, when they likewise will cherish this firm faith. The angels, too, rejoiced with Israel, only God was down-cast on this day and sent His voice "out of thickest darkness," in token of His sorrow.
The angels hereupon said to God: "Is not the joy that Thou hast created Thine?" But God replied: "You do not know what the future will bring." He knew that forty days later Israel would give the lie to the words of God: "Thou shalt have no other gods before Me," and would adore the Golden Calf. And truly, God had sufficient cause to grow sad at this thought, for the worship of the Golden Calf had more disastrous consequences for Israel than any other of their sins.
God had resolved to give life everlasting to the nation that would accept the Torah, hence Israel upon accepting the Torah gained supremacy over the Angel of Death. But they lost this power when they worshipped the Golden Calf. As a punishment for this, their sin, they were doomed to study the Torah in suffering and bondage, in exile and unrest, amid cares of life and burdens, until, in the Messianic time and in the future world, God will compensate them for all their sufferings.
But until that time there is no sorrow that falls to Israel's lot that is not in part a punishment for their worship of the Golden Calf.