For the expounding of this psalm we may borrow a great deal of light from the apostle's discourse, Heb. iii. and iv., where it appears both to have been penned by David and to have been calculated for the days of the Messiah; for it is there said expressly (Heb. iv. 7) that the day here spoken of (ver. 7) is to be understood of the gospel day, in which God speaks to us by his Son in a voice which we are concerned to hear, and proposes to us a rest besides that of Canaan. In singing psalms it is intended, I. That we should "make melody unto the Lord;" this we are here excited to do, and assisted in doing, being called upon to praise God (ver. 1, 2) as a great God (ver. 3-5) and as our gracious benefactor, ver. 6, 7. II. That we should teach and admonish ourselves and one another; and we are here taught and warned to hear God's voice (ver. 7), and not to harden our hearts, as the Israelites in the wilderness did (ver. 8, 9), lest we fall under God's wrath and fall short of his rest, as they did, ver. 10, 11. This psalm must be sung with a holy reverence of God's majesty and a dread of his justice, with a desire to please him and a fear to offend him.
Invitation to Praise God; Motives to Praise.