In a previous post I mentioned that in the story of Exodus 32 God's action is not determined by human behaviour, particularly human failure. This corresponds to the free initiative of God in choosing Israel in the first place. God chose Israel not because of its power or righteousness, but out of love. (See Deut 7:7-8) And because God's free choice of love was not determined by Israel's standing, to then break the covenant by destroying the people because of their abhorrent failure would be a denial of God's freedom. In the same way that God chose Israel not for any reason inherent in Israel (that is, God's action was not conditional upon certain human behaviour), so too God can, in God's freedom, bring a surprising word of forgiveness into the cul-de-sac of human failure. This foundation of the covenant upon the freedom of God also corresponds with the purpose of God's election: our participation in the freedom of God. (See Rom 8:21)
All of this continues seamlessly in the story of Jesus, particularly his crucifixion. The cross of Jesus is a low point in the history of human failure, but it becomes the means for a new and final word of forgiveness for all.
For Pentecost 22(A)
See Hans Urs von Balthasar, Engagement With God, pp. 13-18.