George Haydock's Catholic Commentary
Psalms 21:23
Brethren. So Christ styles his disciples, principally (Calmet) after his resurrection, Matthew xxviii. 10., John xx. 17., and Hebrews ii 11. St. Paul quotes this passage, which may convince us that this psalm relates to our Saviour alone; and he informs us, that we are brethren of Christ, because we spring from Adam, (Berthier) and are adopted by God: whence the apostles assume the title of children of God, after baptism, Romans viii. 15., and 29., and Ephesians i. 5. (Calmet) --- We are willing to be coheirs with Christ, but dislike the condition, Romans viii. 17. --- Church. This he will never cease to do. After the resurrection, he communicated many instructions to his apostles, which all tend to honour God. (Haydock) --- St. Augustine here refutes the Donatists, who pretended that God's church was confined to a small part of Africa, and that he had abandoned the Catholic Church. He shews that this conduct would be injurious to God, and contrary to his solemn promises, as well as to this prediction, which speaks of all, and of a great Church, praising and fearing Him, ver. 24, 26, 28, and 29. The Church can, therefore, neither be destroyed nor hidden, though it may be persecuted. It will always be great, in comparison of any separate congregation which may pretend to the truth; and this appears not only with respect to the Donatists, but also to the Lutherans, &c. (Worthington)