This psalm purports also to be a psalm of Asaph. See Introduction to Psalms 73. In the absence of any evidence to the contrary, it may be assumed to have been composed by or for the Asaph who was the contemporary of David, and who was, appointed by him to preside over the music of the sanctuary. Venema, indeed, supposes that the psalm was composed in the time of Josiah, at the observance of the great Passover celebrated by him 2 Chronicles 35; but there is no positive evidence of this, though there is nothing in the psalm that is inconsistent with such a supposition. On the phrase in the title, upon Gittith, see the notes at the title to Psalms 8:1-9.
The occasion on which the psalm was composed seems to have been a festal occasion, and the circumstances in the psalm will probably best accord with the supposition that it was the Feast of the Passover. Rosenmuller has indeed endeavored to show (see his notes at Psalms 81:4) that it was composed on occasion of the Feast of Trumpets (Leviticus 23:24, following); but there is nothing in the psalm which would necessarily restrict it to that, and, as we shall see, all the circumstances in the psalm harmonize with the supposition that it was at the Feast of the Passover, the principal and the most important festival of the Hebrews. It is well remarked by DeWette (Introduction to the psalm), that as the Hebrews were required to make known to their children the design of the ordinance of the Passover (see Exodus 12:26-27), nothing would be more natural than that the sacred poets should take occasion from the return of that festival to enforce the truths pertaining to it in songs composed for the celebration. Such seems to have been the design of this psalm - reminding the people of the goodness of God in the past, and recalling them from their sins by a remembrance of his mercies, and by a view of what would be the consequences of fully obeying his law.
It would seem from the psalm not improbable that it was composed in a time of national declension in religion, and when there was a tendency to idolatry, and that the object of the author was to rouse the nation from that state, and to endeavor by a reference to the past to bring them back to a more entire devotedness to God.
The contents of the psalm are as follows:
I. The duty of praise, particularly on such occasions as that on which the psalm was composed; a duty enjoined even in Egypt, in the time of Joseph, when God delivered his people out of that strange land, Psalms 81:1-7.
II. The main command which was then ordained to be the guide of the people - the fixed law of the nation - the fundamental idea in their polity - that there was to be no strange god among them, but that they were to worship the true God, and him alone, Psalms 81:8-10.
III. The fact that the nation had refused to hear; that there had been such a proneness to worship other gods, and to fall into the habits of idolaters, that God had given them up to their own desires, and suffered them to walk in their own ways, Psalms 81:11-12.
IV. A statement of what God would have done for them if they had been obedient; of what would have been the effect on their national prosperity if they had hearkened to the commands of God; and consequently of what would still be the result if the people should be obedient, and submit themselves wholly to the law of God, Psalms 81:13-16. Particularly:
(1) Their enemies would have been subdued, Psalms 81:14.
(2) those who hated the Lord would have yielded themselves to him, Psalms 81:15.
(3) God would have given them abundant prosperity; he would have fed them with the finest of the wheat, and would have satisfied them with honey out of the rock, Psalms 81:16.
The psalm is of special importance to the church now, as reminding it of its obligation from the past mercies of God, and as showing what would be the consequences if it should be wholly devoted to the service of God.