Psalm 45 is a hymn celebrating a royal wedding.  It is a love song.

1 – The singer addresses the king, a descendant of David, directly.

2-9 – The king is described as handsome, majestic, and just.  In verse 6 the singer addresses God, who sits above the throne of the Davidic King.  Then the singer describes the divine ideals of how the earthly king should reign, which includes righteousness and which hates wickedness.  These are an admonition to the young king about to be married. These verses also have double meaning as they are cited in Hebrews 1:5 to refer to Christ as the Son, the Son of God, who is superior to the angels. 

10-15 – In verses 10-15, the singer addresses the bride and describes the wedding procession. She is described as beautiful, and she is a princess of a foreign country,

16-17 – Now singer addresses the young king that his sons will continue his line after he is gone.