John Wesley on Exodus 33:20

Thou canst not see my face - A full discovery of the glory of God would quite overpower the faculties of any mortal man. I will make all my goodness pass before thee - He had given him wonderful instances of his goodness in being reconciled to Israel; but that was only goodness in the stream, he would shew him goodness in the spring. This was a sufficient answer to his request: Shew me thy glory, saith Moses; I will shew thee my goodness, saith God. God's goodness is his glory; and he will have us to know him by the glory of his mercy, more than by the glory of his majesty. And I will be gracious to whom I will be gracious - In bestowing his gifts, and is not debtor to any, nor accountable to any; all his reasons of mercy are fetched from within himself, not from any merit in his creatures, and I will shew mercy on whom I will shew mercy - For his grace is always free. He never damns by prerogative, but by prerogative he saves.