Why did Israel get suckered into the idolatry of Peor, at the instigation of Balaam (Num 25:1-3, Num 31)? Perhaps Balaam convinced them that they were already chosen; they had already been delivered from death by the blood of the Passover lamb and had gone through the Red Sea (1 Cor 10:1-2). They were already in covenant with the Lord God, cut at Mt. Sinai. Did not God just bless them and prophesy awesome and wonderful things about them (Num 23-24)?
Therefore, their identity as His people, he may have argued to them, negated the necessity of “works befitting repentance” (Act 26:20), a doctrine which the Lord declared heretical by killing those who indulged in the doctrine of Balaam with a plague from His hand (Num 25:1-9). If this is a correct understanding of the doctrine of Balaam, then this heresy is closely related to that of the Nicolaitans.
“[The doctrine of Balaam] is stated in the subsequent part of the verse: ‘Who taught Balak to cast a stumbling-block before the children of Israel.’ … The meaning here is, that it was through the instructions of Balaam that Balak learned the way by which the Israelites might be led into sin, and might thus bring upon themselves the divine malediction. … The attitude of Balaam’s mind in the matter was this: i. He had a strong desire to do that which he knew was wrong, and was forbidden expressly by God. ii. He was restrained by internal checks and remonstrances, and prevented from doing what he wished to do. iii. He cast about for some way in which he might do it, notwithstanding these internal checks and remonstrances, and finally accomplished the same thing in fact, though in form different from that which he had first prepared. This is not an unfair description in what often occurs in the plans and purposes of a wicked man.”
Albert Barnes, Notes on … Revelation, pp. 75-76.
Christine’s note: Barnes makes a cogent case that Balaam’s sin was in obeying the letter of the law while violating the spirit of it.
“Compare Re 2:14, 15, which shows the true sense of Nicolaitanes; they are not a sect, but professing Christians who, like Balaam of old, tried to introduce into the Church a false freedom, that is, licentiousness; …”
Jamieson, Faussett, and Brown, Commentary, Revelation 2:6.