What does Psalm 45:17 mean?

The psalmist wrote for an earthly king's marriage (Psalm 45:1, 9). However, his words also serve to predict the ministry of the ultimate King, Jesus Christ (Psalm 45:6–7; Hebrews 1:8–9). Poetic exaggeration was—and is—a common trait of songs about love or celebrated rulers (Psalm 45:2–5). So, too, were ancient claims that a king would never be forgotten. The psalmist assures the king that all future generations will praise him.

These words apply ultimately—and much more literally—to the King of kings and Lord of lords (1 Timothy 6:15; Revelation 17:14; 19:16). His people remember Him now in the ordinance of the Lord's Supper (1 Corinthians 11:23–26), but this is a remembrance of His death. In eternity His redeemed people of all ages will remember not only His death but also His victory over death and His glorious reign. Revelation 5:9–10 records the words of the four living creatures and twenty-four elders in heaven, "Worthy are you [Jesus] to take the scroll and to open its seals, for you were slain, and by your blood you ransomed people for God from every tribe and language and people and nation, and you have made them a kingdom and priests to our God, and they shall reign on the earth." Thousands of thousands of angels join in (Revelation 5:11–12). The chapter closes with a resounding crescendo of voices—"every creature in heaven and on earth and under the earth and in the sea, and all that is in them"—ascribing blessing and honor and glory to God and the Lamb [Jesus] "forever and ever" (Revelation 5:13). The four living creatures say "Amen," and the twenty-four elders fall down in worship (Revelation 5:14).