Charles H. Spurgeon on Psalms 81:9

There shall no strange god be in thee. No alien god is to be tolerated in Israel's tents. Neither shalt thou worship any strange god. Where false gods are, their worship is sure to follow. Man is so desperate an idolater that the image is always a strong temptation: while the nests are there the birds will be eager to return. No other god had done anything for the Jews, and therefore they had no reason for paying homage to any other. To us the same argument will apply. We owe all to the God and Father of our Lord Jesus Christ: the world, the flesh, the devil, none of these have been of any service to us; they are aliens, foreigners, enemies, and it is not for us to bow down before them. "Little children keep yourselves from idols, "is our Lord's voice to us, and by the power of his Spirit we would cast out every false god from our hearts.