Today's reading deals with one of the most common reasons people leave churches: the presence of sin. Calvin argues that while we should grieve over sin, oppose it, and pursue holiness, we must not confuse the imperfections of the visible church with the absence of the true church. The temptation to separate often springs less from genuine zeal for God's holiness than from pride, impatience, or an unrealistic expectation of perfection this side of heaven. The church is holy because Christ is making her holy—not because she has already reached perfection.

In these sections of the Institutes, Calvin confronts the spirit of schism. Drawing from Augustine, Cyprian, the prophets, Christ, and the apostles, he insists that believers should patiently bear with the faults they cannot correct while faithfully working to reform what they can. ...