This Psalm is a Messianic Psalm; these are Psalms which foretell some aspect of the life of Christ.  In this Psalm we see the coronation of Christ as King.  It begins by describing the actions of the nations that reject the rule of God and His Son (1-3).  Then moves into God’s response to their rejection (4-5).  After that we see the installation of Christ as King and His earthly rule (6-9), which is a prophetic reference to Christ’s Millennial reign.  Finally, this Psalm ends with an invitation to the nations of the earth to put their trust in Christ (10-12)