Daily Office Lections: Haggai 1:1-15; Revelation 2:18-29; Matthew 23:27-39
Whereas the church at Ephesus did not tolerate false teachers but had lost their first love, the church at Thyatira was engaged in works of love but did tolerate false teachers, namely, "Jezebel." This is almost certainly a nickname for the false prophetess meant to recall the Jezebel from the Old Testament, wife of King Ahab, who, though not a prophet, led Israel into spiritual adultery.
While the reference to adultery in verse 22 could certainly include the particular sin, it seems that it is speaking more directly to spiritual adultery, to the Church's unfaithfulness to her bridegroom -- Jesus Christ. Throughout Scripture, unfaithfulness to the God, with whom his people are in covenant, is referred to as such.
Thus, to believe and practice that which is contrary to the "that which ye have already" (v. 25) is to engage in adultery. Moreover, to allow false teaching in the Church, to bear it, is adulterous as well, and harmful to the members of the body. Many of the letters of the New Testament are written with the express purpose of combatting false teaching so that the souls of the faithful are not poisoned.
We are beset in our day with all manners of heresies and false teachings. We must, as Christ is urging the church at Thyatira, hold on to the faith that we have received, speaking and walking according to it. We must be bold even when the teachings of Christianity are profoundly out of kilter with the spirit of the age (which they are).
So let us cast off the works of darkness, heed the warnings of the prophets, and our Lord himself, hold fast to the truth, becoming in practice a faithful bride so that we may rule and reign with him in the age to come.