“What, then, are some of the reasons why Christians should sing only “the Book of Psalms” in praise to God?
1. The command of God Jam. 5:13, which ought to be sufficient for every saint.
2. He has given to us no additional hymns in the New Testament, for the Book of Psalms was previously perfect.
3. Because Christ, “in whom dwells all the fulness of the Godhead bodily,” who is “the wisdom of God,” and in whom dwells all the “fulness of knowledge and of wisdom,” not only made no new ones, but consoled himself, on the cross, with the words of David. Psa. 22:1; 31:5. This is the highest possible authority to every Christian, for the use of the Psalms exclusively.
4. Because the apostles, although inspired to write the New Testament, and to complete the word of God, were not “moved by the Holy Ghost” to write any more “spiritual songs.” We have their Gospels, Acts, and Epistles, yet they leave us nothing with which to supplant the songs of Zion.
5. Because every human composition lacks divine appointment. The command is not, make “a psalm,” but “take” one. Psa. 81:2.
6. Because the Psalms are vitally adapted to our use. When we search the other scriptures, we learn how others served God; when we sing “the Lord’s song” aright, we worship him ourselves. Psa. 63:3-5.
7. Because, the psalms being given by the same Spirit who regenerates every Christian, they are precisely adapted to the growth of the soul in the divine life, being “the sincere milk of the word,” by which the believer grows 1 Pet. 2:2, when he “lets the word of Christ dwell in him richly.”
8. Again, when “all nations shall call Christ blessed,” his “watchmen shall sing together with the voice.” Isa. 52:8. “They shall lift up their voice, until from the uttermost parts of the earth shall be heard songs, even glory to the righteous.” Isa. 24:14-16. As they shall then see eye to eye, they will sing together, in the unity of the faith, “the song of Jehovah” Psa. 137:4,—that song which, given under the Old Testament dispensation, was “the song of moses,” and which, being perpetuated coextensively with the reign of Messiah, is forever “the song of the Lamb.” Psa. 86:8-10; Rev. 15:3,4.” — Alexander Blaikie, “A Catechism on Praise”