Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(Psa 81:1-7) God is praised for what he has done for his people.
(Psa 81:8-16) Their obligations to him.
All the worship we can render to the Lord is beneath his excellences, and our obligations to him, especially in our redemption from sin and wrath. What God had done on Israel's behalf, was kept in remembrance by public solemnities. To make a deliverance appear more gracious, more glorious, it is good to observe all that makes the trouble we are delivered from appear more grievous. We ought never to forget the base and ruinous drudgery to which Satan, our oppressor, brought us. But when, in distress of conscience, we are led to cry for deliverance, the Lord answers our prayers, and sets us at liberty. Convictions of sin, and trials by affliction, prove his regard to his people. If the Jews, on their solemn feast-days, were thus to call to mind their redemption out of Egypt, much more ought we, on the Christian sabbath, to call to mind a more glorious redemption, wrought out for us by our Lord Jesus Christ, from worse bondage.
We cannot look for too little from the creature, nor too much from the Creator. We may have enough from God, if we pray for it in faith. All the wickedness of the world is owing to man's wilfulness. People are not religious, because they will not be so. God is not the Author of their sin, he leaves them to the lusts of their own hearts, and the counsels of their own heads; if they do not well, the blame must be upon themselves. The Lord is unwilling that any should perish. What enemies sinners are to themselves! It is sin that makes our troubles long, and our salvation slow. Upon the same conditions of faith and obedience, do Christians hold those spiritual and eternal good things, which the pleasant fields and fertile hills of Canaan showed forth. Christ is the Bread of life; he is the Rock of salvation, and his promises are as honey to pious minds. But those who reject him as their Lord and Master, must also lose him as their Saviour and their reward.