7 Behold, “Be the Lord magnified:” will you never, will you nowhere? In Him was something, in me nothing: but if in Him is whatsoever I am, be He, not I. But thou then what? “But I am needy and poor”. He is rich, He abounding, He needing nothing. Behold my light, behold whence I am illumined; for I cry, “You shall illumine my candle, O Lord.” What then of you? “But I am needy and poor.” I am like an orphan, my soul is like a widow destitute and desolate: help I seek, always mine infirmity I confess. There have been forgiven me my sins, now I have begun to follow the commandments of God: still, however, I am needy and poor. Why still needy and poor? Because “I see another law in my members fighting against the law of my mind.” Why needy and poor? Because, “blessed are they that hunger and thirst after righteousness.” Still I hunger, still I thirst: my fullness has been put off, not taken away. “O God, aid me.” Most suitably also Lazarus is said to be interpreted, “one aided:” that needy and poor man, that was transported into the bosom of Abraham; and bears the type of the Church, which ought always to confess that she has need of aid. This is true, this is godly. “I have said to the Lord, My God You are.” Why? “For my goods You need not.” He needs not us, we need Him: therefore He is truly Lord. For you are not the very true Lord of your servant: both are men, both needing God. But if you suppose your servant to need you, in order that you may give him bread; thou also needest your servant, in order that he may aid your labours. Each one of you does need the other. Therefore neither of you is truly lord, and neither of you truly servant. Hear thou the true Lord, of whom you are the true servant: “I have said to the Lord, My God You are.” Why are You Lord? “Because my goods You need not”? But what of you? “But I am needy and poor.” Behold the needy and poor: may God feed, may God alleviate, may God aid: “O God,” he says, “aid me.”
8. “My helper and deliverer are You; O Lord, delay not.” You are the helper and deliverer: I need succour, help Thou; entangled I am, deliver Thou. For no one will deliver from entanglings except You. There stand round about us the nooses of various cares, on this side and on that we are torn as it were with thorns and brambles, we walk a narrow way, perchance we have stuck fast in the brambles: let us say to God, “You are my deliverer.” He that showed us the narrow way, has taught us to follow it....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)