New Defender's Study Bible Notes
144:15 Happy is that people. The word “happy” (or “blessed”) is used twice in this concluding verse of his next-to-last psalm of Book IV of the Psalms (see note on Psalm 145:21).
Psalm 145 (title) Psalm of Praise. This is the only psalm headed as “Psalm of Praise.” However, see note on Psalm 100.