14 “Cleanse me, O Lord, from my secret faults.” From the lusts which lie hidden in me, cleanse me, O Lord. “And from the” faults “of others preserve Your servant”. Let me not be led astray by others. For he is not a prey to the faults of others, who is cleansed from his own. Preserve therefore from the lusts of others, not the proud man, and him who would be his own master, but, Your servant. “If they get not the dominion over me, then shall I be undefiled.” If neither my own secret sins, nor those of others, get the dominion over me, then shall I be undefiled. For there is no third source of sin, but one's own secret sin, by which the devil fell, and another's sin, by which man is seduced, so as by consenting to make it his own. “And I shall be cleansed from the great offense.” What but pride? For there is none greater than apostasy from God, which is “the beginning of the pride of man.” And he shall indeed be undefiled, who is free from this offense also; for this is the last to them who are returning to God, which was the first as they departed from Him.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)