Ps 33:3

“Now followeth, "O magnify the Lord with me" (ver. 3). Who is this that exhorteth 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 loveth the Lord, whoever he is. And how doth 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 loveth a charioteer or hunter, wisheth the whole people to love with him, and exhorteth, saying, Love with me this pantomime, love with me this or that shame. He calleth among the people that shame may be loved with him; and doth 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 ye 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."”

“Then when he says, "Magnify," he exhorts to praise. And first to interior praise. Second, to exterior, at "And let us exalt." As to the first he says, "Magnify the Lord with me." To magnify and to praise God are the same thing, because the goodness of God and his greatness are the same; because in those things that are not great in bulk, to be greater is the same as to be better, according to Augustine in On the Trinity. And therefore he says, "Magnify": Lk. 1: "My soul magnifies the Lord." And this corresponds to what he says, "I will bless the Lord." As to the second he says, "And let us exalt his name." That which is high in itself is said to be exalted when it is spread among many: Sir. 43: "Glorifying the Lord, exalt him as much as you can," etc. "Together," that is, in concord. And this corresponds to what he says, "His praise is always in my mouth."”