Prayers in the Psalms

Many of the prayers in the Old Testament are to be found in the book of the Psalms. A number of psalms play an important part in the Temple liturgy:

Psalms 113–118, known in Judaism as the “Egyptian Hallel”, were spoken at Passover and the Harvest Festival. This custom was maintained in the later liturgy of the synagogues.
The Psalms of the “daily Hallel” (Psalms 146–150; Psalms 135–136) were probably used in liturgy, possibly during the three great festivals (Passover, the Harvest Festival and the Festival of Shelters), or in the daily liturgy of the Levites in the Temple in Jerusalem.