Hallel of pesukei dezimra a selection of six psalms recited as part of pesukei dezimra — the introduction the daily morning service. This "Hallel" is specifically Ashrei (most of which is Psalm 145) followed by Psalms 146-150. The term Hallel without a qualifier general refers to Psalms 113-118 which are recited only of festivals; for this reason the Hallel of pesukei dezimra is also known as the "daily Hallel".
These psalms are recited because they are devoted entirely to the praise of God.[1]
Originally, this was the only part of pesukei dezimra. Its recitation was considered voluntary for a long time.[2]
There are contradictory views on the daily recitation of Hallel. The Gemara refers to one who recites Hallel daily as a blasphemer. Talmud Bavli refers to one who recites it daily as praiseworthy. The recitation of these six psalms as an alternative to 113-118 is a compromise on this matter.[3]