The book of Psalms ends with a series of praises of God. Psalms is a very complex book. Some psalms deal with praising God. Others deal with the pain of feeling exiled from God. Others deal with asking God for our basic needs. However, at the end of the day, we should always return to the praise of God, for that is the end for which we were created. The Psalmist first invokes the praise of the angels and saints in heaven, who serve to praise God without end.
Praise the Lord! Praise the Lord from the heavens, praise him in the heights! Praise him, all his angels, praise him, all his host!
Christ is risen from the dead,
By death trampling down on death,
And to those in the tomb,
He has granted life!