It’s difficult to read Scripture with the eyes of faith and not come away with an optimistic view of the future in light of the myriad promises of God that are breathtaking in scope and which promise success for the spread of the gospel. Though most of the Psalms are laments, the Psalms especially are filled with such global optimism and promises for the successful reign of Christ. Keith Mathison, in his excellent book Postmillennialism: An Eschatology of Hope, devotes an entire chapter to the optimism of the Psalms. His summary at the end of the chapter is especially helpful, and I quote it here:
“In each of the psalms we have examined, a different facet of the reign of the Messiah is brought to light:
1. Psalm 2. Christ is the rightful heir of all the nations.
2. Psalm 22. The same Christ who was crucified and is now exalted will fulfill the Abrahamic promise, and all the nations of the earth will remember and turn to God.
3. Psalm 47. All nations of the earth will be united to Christ and will become the one people of the God of Abraham.
4. Psalm 67. Although national Israel has failed, Christ will succeed as the mediator of the Abrahamic blessing to the nations of the earth.
5. Psalm 72. The people of God should faithfully pray for Christ to have worldwide dominion, to have all nations bow before Him, and to have all nations call Him blessed.
6. Psalm 86. The same omnipotent God who made all the nations will convert all the nations.
7. Psalm 110. Christ will reign from the right hand of God until He has brought all His enemies into either willing or unwilling submission.
“The Psalms continue to expand upon the covenant promises of the Pentateuch and the Historical Books by expressing Israel’s faith in the sure fulfillment of those promises. In doing so, they reinforce the postmillennial foundation, even as they begin to build upon it.”
-Keith Mathison in Postmillennialism: An Eschatology of Hope (P&R, 1999), pp. 81-82