Psalm 21

O LORD, in your strength the king rejoices!” David, the author of this song, was one of Israel’s greatest kings. Yet in Psalm 21 he seems to be writing about a more highly exalted ruler.
God had fulfilled that great leader’s requests, but what were the desires that the Lord granted? “Length of days forever and ever.” “You make him most blessed forever.” “The Lord will swallow (the king’s enemies) up in his wrath, and fire will consume them.” These words sound like Judgment Day and not the victory of anyone in the history of the Old Testament people. “You will destroy their descendants from the earth, and their offspring from among the children of man.”
The king trusts in the Lord.” He is somehow different from God and yet possesses the blessings of God-like authority and power. To find the fulfillment of these verses we need to look beyond the earthly ministry of Jesus of Nazareth and join the Apostle John as he gazed with awe upon the exalted heavenly Christ in Revelation 1.
The ruling Messiah has become the Lord’s final answer to our prayers. He is no longer dying on the cross. He is the reigning ascended Jesus who has all power and authority in heaven and on earth. As the author of Hebrews says, “See that you do not refuse him who is speaking. For if they did not escape when they refused him who warned them on earth, much less will we escape if we reject him who warns from heaven.” (Hebrews 12:25) In the concluding words of Psalm 21, “Be exalted, O LORD, in your strength! We will sing and praise your power.”
Prayer from A Book of Prayers

Mighty God, we rejoice in Your strength and in the glory of Your Son, the King over Your people. He is full of splendor and majesty, for He has trusted perfectly in You, O God. Your day of wrath is coming, and You will separate the wicked from the righteous. Be exalted, in the greatness of Your perfect power.