What does Psalm 45:8 mean?

Myrrh is pleasant-smelling resin from trees in Arabia. It was used as a perfume (Proverbs 7:17). Aloes were also used for their fragrance (Numbers 24:6; Proverbs 7:17). Cassia was another perfume derived from roots or bark which might have resembled cinnamon. In reference to the wedding of an earthly king (Psalm 45:1, 9), these depict a lavishly dressed, impressive figure. Myrrh and aloe, however, were also used to prepare bodies for burial (Matthew 2:11; John 19:39). This is another point which connects this psalm to the then-future work of the Messiah, Jesus Christ.

Ivory has always been a relatively expensive material, suitable for ornate objects (1 Kings 10:18). To use it as an element of a home's design would be extravagant (Amos 3:15; Song of Solomon 7:4). The imagery here is that of a lavish, gorgeous environment filled with beautiful music. As far as it applies to the literal wedding of an earthly king (Psalm 45:1), this is part of celebrating the joyous occasion.

The same imagery also serves to foreshadow the joyful occasion when King Jesus leaves heaven to be joined in marriage to His bride (1 Thessalonians 4:13–18). Revelation 19:6–8 anticipates Jesus' return to from heaven to celebrate the marriage supper. A person whose walls were inlaid with ivory was considered wealthy. King Ahab's house is described as "the ivory house" (1 Kings 22:39), but the place Jesus is preparing for believers is far superior to any earthly ivory house (John 14:3).