Moses well knew that mercy was God's chief virtue. He remembered that he had asked God, when he interceded for Israel after their sin of the Golden Calf, "Pray tell me by what attribute of Thine Thou rulest the world." God answered: "I rule the world with loving-kindness, mercy, and long-suffering." "Can it be," said Moses, "that Thy long-suffering lets sinners off with impunity?"
To this question Moses had received no answer, hence he felt he might now say to God: "Act now as Thou didst then assent. Justice, that demands the destruction of Israel, is on one side of the scales, but it is exactly balance by my prayer on the other side. Let us now see how the scales will balance." God replied: "As truly as thou livest, Moses, thy prayer shall dip the scales to the side of mercy.
For thy sake must I cancel My decision to annihilate the children of Israel, so that the Egyptians will exclaim, 'Happy the servant to whose wish his master defers.' I shall, however, collect My debt, for although I shall not annihilate Israel all at once, they shall make partial annual payments during the following forty years. Say to them, 'Your carcasses shall fall in this wilderness; and all that were numbered of you, according to your whole number, from twenty years old and upward, which have murmured against Me.
And your children shall be wanderers in the wilderness forty years, and shall bear you whoredoms, until your carcasses be consumed in the wilderness.'"