15 “And the words of my mouth shall be pleasing, and the meditation of my heart is always in Your sight”. The meditation of my heart is not after the vain glory of pleasing men, for now there is pride no more, but in Your sight always, who regardest a pure conscience. “O Lord, my Helper, and my Redeemer”. O Lord, my Helper, in my approach to You; for You are my Redeemer, that I might set out unto You: lest any attributing to his own wisdom his conversion to You, or to his own strength his attaining to You, should be rather driven back by You, who resistest the proud; for he is not cleansed from the great offense, nor pleasing in Your sight, who redeemest us that we may be converted, and helpest us that we may attain unto You.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)