God does not grant His mercy [and grace] to some people because they know Him, but in order that they may know Him. Nor is it because they are upright in heart, but that they may become so, that He grants them His righteousness by which He justifies the ungodly. This thought does not inflate us with pride! The sin of pride arises when anyone has too much self-confidence, and makes himself the supreme reason for living. Driven by this conceited feeling, the proud person departs from the Fountain of life, from Whose streams alone we can drink the holiness which is itself the good life. Yes, the proud person departs from that unchanging Light, by sharing in which the rational soul is set on fire (so to speak) and becomes a created and reflected light.
Augustine (354-430), On the Spirit and the Letter, 11 in N. R. Needham, The Triumph of Grace: Augustine’s Writings on Salvation, 191-92.