Psalm 69 is a surprising Psalm to be messianic. It ends well, but most of the Psalm is a desperate cry for help from someone who knows he has done wrong, and then a plea for God to do worse to his enemies than they did to him. "May they have no acquittal from You," the Psalmist says to God.
(Jesus' fulfillment of Scripture is in the 23rd verse, "They gave me poison for food and for my thirst they gave me sour wine to drink.")
Of all the Scriptures, in the Psalms we see the clearest, most honest, picture of our humanity. We see our doubts and our Hope; our anger and our joy; our neediness and our glory--made just a little lower than the angels!
But the Psalms are also the most prophetic of the Old Testament Scriptures in showing us who the Messiah would be.
I wonder, was there anyone who was so human as our Saviour? What a magnificent mystery is the incarnation!