10 Nay more, if a whole people sin, this surpasses not the loving-kindness of God. The people made a calf, yet God ceased not from His loving-kindness. Men denied God, but God denied not Himself. These be your gods, O Israel, they said: yet again, as He was wont, the God of Israel became their Saviour. And not only the people sinned, but also Aaron the High Priest. For it is Moses that says: And the anger of the Lord came upon Aaron: and I prayed for him, says he, and God forgave him. What then, did Moses praying for a High Priest that sinned prevail with God, and shall not Jesus, His Only-begotten, prevail with God when He prays for us?
And if He did not hinder Aaron, because of his offense, from entering upon the High Priesthood, will He hinder you, who has come out from the Gentiles, from entering into salvation? Only, O man, repent thou also in like manner, and grace is not forbidden you. Render your way of life henceforth unblameable; for God is truly loving unto man, nor can all time worthily tell out His loving kindness; nay, not if all the tongues of men unite together will they be able even so to declare any considerable part of His loving-kindness. For we tell some part of what is written concerning His loving-kindness to men, but how much He forgave the Angels we know not: for them also He forgives, since One alone is without sin, even Jesus who purges our sins. And of them we have said enough.
Source: Catechetical Lectures (New Advent)