“Christ and His Church constitute one body in a union more intimate than that of the human body and spirit, and why should not the voice of Christ mystical speak in the Psalter, so that in some passages we hear the voice of the Head, and in others the voice of the members, both being the voice of the one Christ? And thus confessions of sin and claims of innocence may both be true and appropriate in the mouth of the one mystical Person.”
“Today, the Christian Church sings the Psalms with an understanding superior to what the Jewish Church had. Only after the coming of Christ could God’s people sing the Psalms with a clarity about the King, his kingdom, and the eschatological victory which will be sealed for his Church by his coming. God meant the Psalms for his Church in this age: whatever things were written before were written for our learning and admonition, upon whom the end of the ages have come (Romans 15:4, 1Corinthians 10:11). And God meant the Psalms to edify and bless his people.”
“Though the “Book of Praises” was gathered during the OT era and used in the Temple’s
worship, its full intent as a canon of praise could not be fully grasped until Christ came. Its intent was to reveal and praise the Savior-King who would fulfill all the promises of God’s covenant with Israel. Jesus Christ must therefore be understood as the Sovereign of the Psalter, but also as the source of and the purpose for the development of the canon of the Psalter.”
“When you sing the Psalms, you are actually singing the songs of Jesus, with Jesus as your songleader. That is an exciting thought. It is an exciting thought celebrated in the book of Hebrews with these words: ‘[Jesus]… is not ashamed to call them brothers, saying “I will tell of your name to my brothers; in the midst of the congregation I will sing your praise’” (Heb. 2:11-12, quoting Ps. 22:22). It is King Jesus who takes the Davidic Psalms to his lips and sings them ‘in the midst of the congregation’ – and he invites us to join his songs with him. No other praise song can do that… it is in the biblical Psalms alone that Jesus himself, our priestly king, leads our sung proclamations in the presence of the Father.” 
“The particular collection of 150 Psalms preserved in the canon was prepared in the post-exilic period, when there was no longer a king in Jerusalem. Arguably, the edition of the Psalter contained in the Bible is a selection of Psalms, specifically chosen and compiled for the expected Messiah.”
“[The] anticipated Messiah has come, and his name is Jesus. And the Psalms are his songs. Many modern hymns are written to Jesus, or are written about Jesus. The Psalms also include portions addressed to Christ and many lines about him. But in all the Psalms (and only in the Psalms) we have words of Christ to sing with him… [uninspired songs] can speak about Jesus, but they cannot give us the voice of Jesus.”
“Sung praise is an act of confession in the midst of the congregation, and one which our Lord Jesus Christ, as the Elder Brother and Superintendent of the Sanctuary, claims a sole prerogative to lead. Heb. 2:12.”
1. McKitrick, E.S. “Christ in the Psalms” in The Psalms in Worship (1907), edited by John McNaughter. Edmonton: Still Waters Revival Books, 1992, page 235.
2. RPCNA Synod’s Study Committee on Worship. “The Psalms in the Worship of the Church.” Submitted to the Synod of the RPCNA, June 2004. First Reformed Presbyterian of Cambridge. PDF article.
4. Lefebvre, Michael. Singing the Songs of Jesus. Rosshire, Scotland: Christian Focus Publications, 2010, page 51.
5. Ibid. page 53, footnote 28.
6. Ibid. page 92-93.
7. Winzer, Matthew. “What is the scriptural warrant to confine song in public worship to Psalms only?” (reply to thread) Puritanboard (Web forum) May 19, 2009 (6:01 p.m.).