The Book of Psalms, even if it is, properly speaking, the third part of the Old Testament, as Our Lord says in Luke 24:44, "all things must needs be fulfilled which are written in the law of Moses and in the prophets and in the psalms, concerning me," nevertheless is also a sort of summation or as it were a compendium of all of Sacred Scripture. For the Book of Psalms contains accounts from sacred history, as is evident from Psalms 77, 103, 104 and others; it contains many very plain prophetic oracles, as is evident from Psalms 2, 21, 44, 60 and others; it contains laws and precepts, as is evident in Psalm 118; it contains "hagiographa" in almost all the Psalms, that is, exhortations to virtue, discouragement from vice, threats, promises, examples, remedies for vices, divine praises, prayers to God, in short a complete, natural, moral and supernatural theology.