5 Now follows, “O magnify the Lord with me”. Who is this that exhorts us, that we should magnify the Lord with him? Whoever, Brethren, is in the body of Christ, ought for this to labour, that the Lord may be magnified with him. For he loves the Lord, whoever he is. And how does he love Him? So as not to envy his fellow-lover....Let them blush who so love God as to envy others. Abandoned men love a charioteer, and whoever loves a charioteer or hunter, wishes the whole people to love with him, and exhorts, saying, Love with me this pantomime, love with me this or that shame. He calls among the people that shame may be loved with him; and does not a Christian call in the Church, that the Truth of God may be loved with him? Stir up then love in yourselves, Brethren; and call to every one of yours, and say, “O magnify the Lord with me.” Let there be in you that fervour. Wherefore are these things recited and explained? If you love God, bring quickly to the love of God all who are joined unto you, and all who are in your house; if the Body of Christ is loved by you, that is, if the unity of the Church, bring them quickly to enjoy, and say, “O magnify the Lord with me.”
6. “And let us exalt His Name together.” What is, “let us exalt His Name together”? That is, in one. For many copies so have it, “O magnify the Lord with me; and let us exalt His Name in one.” Whether it be said, “together,” or “in one,” it is the same thing. Therefore bring quickly whom you can, by exhorting, by transporting, by beseeching, by disputing, by rendering a reason, with meekness, with gentleness. Bring them quickly unto love; that if they magnify the Lord, they may magnify Him in one....
7. “I sought the Lord, and He heard me”. Where heard the Lord? Within. Where gives He? Within. There you pray, there you are heard, there you are blessed. You have prayed, you are heard, you are blessed; and he knows not who stands by you: it is all carried on in secret, as the Lord says in the Gospel, “Enter into your closet, and when you have shut your door, pray to your Father which is in secret; and your Father which sees in secret, shall reward you openly.” When therefore you enter into your chamber, you enter into your heart. Blessed are they who rejoice when they enter into their heart, and find therein nought of evil....
8. “I sought the Lord, and He heard me.” Who then are not heard, seek not the Lord. Attend, Holy Brethren; he said not, I sought gold from the Lord, and He heard me; I sought from the Lord long life, and He heard me; I sought from the Lord this or that, and He heard me. It is one thing to seek anything from the Lord, another to seek the Lord Himself. “I sought” (says he) “the Lord, and He heard me.” But you, when you pray, saying, Kill that my enemy, seekest not the Lord, but, as it were, makest yourself a judge over your enemy, and makest your God an executioner. How do you know that he is not better than thou, whose death you seek? In that very thing haply he is, that he seeks not yours. Therefore seek not from the Lord anything without, but seek the Lord Himself, and He will hear you, and while thou yet speakest, He will say, “Lo, here I am.”...
Source: The Enarrations, or Expositions, on the Psalms (New Advent)