Deuteronomy 32:5

Their spot - The wickedness with which they are stained, is not of his children - Plainly shews they are not his children, but the devil's. God's children have no such spot.

They have corrupted themselves,....

Their spot is not the spot of his children. Even God's children have their spots, while they are in this imperfect state; for if we say we have no sin, no spot, we deceive ourselves. But the sin of Israel was none of those; it was not an infirmity which they strove against, watched and prayed against, but an evil which their hearts were fully set in them to do.

They have corrupted themselves--that is, the Israelites by their frequent lapses and their inveterate attachment to idolatry. their spot is not the spot of his children--This is an allusion to the marks which idolaters inscribe on their foreheads or their arms with paint or other substances, in various colors and forms--straight, oval, or circular, according to the favorite idol of their worship.

THERE are frequently great difficulties in identifying the persons of men even when they have been distinctly seen. Our police courts have given us, during the last few weeks, most serious evidence that men may be utterly deceived as to the identity of individuals. They may be prepared, and honestly, I believe, to take an oath that such-and-such a person is the man whom they saw discharging firearms or throwing stones, and yet that person may have been many miles away. A slight change of dress, another color in the necktie or a different shape of the hat—or some trifling alteration of the hair may throw a witness entirely off his guard. It was said to be almost dangerous for persons of a certain height, and of a certain color of hair, to be passing the police courts lest they should be arrested, and marched in with others to be identified by witnesses who were extremely anxious to identify somebody or other. This fact seems very clearly established—that the judgment of men, even with regard to the identity of their fellow creatures—is very far from being infallible. Turning to the moral universe, identity there is far more difficult to be made out, for both the moral and religious world swarm with pretenders. You cannot know for certain who among your acquaintances is a Christian and who is not. This is known to God and may be revealed to each man for himself. But deception is so easy and is nowadays practiced in so masterly a manner that I know it is difficult to know a son of God from a son of Belial. You may sit down and commune with an Apostle and find he is a Judas! You may walk side by side with one who seemed to be a Simon Peter and prove him to be a Simon Magus. Yes, what is worse, you may be deceived about yourself, and whereas you may have thought your body to be a temple of the Holy Spirit, you may suddenly discover it to have been made a den of thieves.