John Gills Exposition of the Bible Commentary - Psalms 81:5
This he ordained in Joseph for a testimony ,.... That is, this law concerning the blowing of trumpets on the new moon, and the keeping the solemn feast at the full of the moon, was made to be observed by all Israel, who are meant by Joseph, for a testimony of God's good will to them, and of their duty and obedience to him: when he went out through the land of Egypt , or "over it" F2 בצאתו על ארץ "in ipsum exeundo", Montanus; "cum exiret ipse super terram", Pagninus. ; which... read more
Matthew Henry's Complete Commentary - Psalms 81:1-7
When the people of God were gathered together in the solemn day, the day of the feast of the Lord, they must be told that they had business to do, for we do not go to church to sleep nor to be idle; no, there is that which the duty of every day requires, work of the day, which is to be done in its day. And here, I. The worshippers of God are excited to their work, and are taught, by singing this psalm, to stir up both themselves and one another to it, Ps. 81:1-3. Our errand is, to give unto... read more