The New Testament Teaches Us To See Christ In All The Psalms

In Luke 4:11, Satan tempts Christ by quoting to him Psalm 91:11-12, where God "will command his angels concerning you to guard you in all your ways. On their hands they will bear you up, lest you strike your foot against a stone." If this account had not been included in the Gospels, we might never have known that Psalm 91 is all about Christ.

In the book of Acts, Psalm 16:10 is twice quoted by the apostles, and by them it's revealed that Christ is the speaker in that Psalm. Again, if these statements by the apostles hadn't been recorded, we might never have known that Psalm 16 is all about Christ.

Psalms 91 and 16 are typical of the language of many other Psalms. There is no reason to assume that the words and prayers in many other Psalms are not the prayers of Christ, or words about him, I believe that this is what we are to infer from the many other New Testament references to Christ in the Psalms.

The resurrected Christ himself told his slow-to-understand disciples, "These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me" (Luke 24:44).

So, the New Testament lets us know to look for our Good Shepherd in the Psalms; either for his voice in the "first person" or for words about him. 

One common argument against singing only the Psalms in the worship and praise of God is that in singing them we are not singing the name of Jesus. Yet, in singing the Psalms, we're singing both about him and with him. We are singing what he is singing, what he desires to sing in the congregation (Psalm 22:22-25; Hebrews 2:11-13). He will not sing our uninspired words, but will sing his own words, leading the churches in the praising, thanking, and petitioning the Father.