Christ was quoting from Psalm 110. It is very difficult to classify the Psalms according to theme, but the following is a rough approximation which may be helpful. Psalms of Praise - A number of the Psalms are aimed at extolling the nature of God as His divinity is observed in both His works and His word. Psalm 19 is an excellent example. Consider Psalm 105.
Great lessons are to be learned from history.
Ethical Psalms - Some of the Psalms emphasize the origin and nature of man. They stress his moral responsibility and ultimate accountability. Note the ethical implications of Psalm 1, where the spiritual person is described as one who does not walk in the counsel of the wicked, nor stand in the way of sinners, nor sit in the seat of scoffers. They acknowledge the fact that evil conduct is an assault upon the Creator, and they evince a deep feeling of contrition as a consequence of offending Jehovah. The spirit of these poems surely stands in bold relief to the flippant attitude toward sin that is so characteristic of today's world.