From Warnings To The Churches by J.C. Ryle (1816-1900):
Divisions and separations are most objectionable in religion. They weaken the cause of true Christianity…But before we blame people for them, we must be careful that we lay the blame where it is deserved. False doctrine and heresy are even worse than schism. If people separate themselves from teaching that is positively false and unscriptural, they ought to be praised rather than reproved. In such cases separation is a virtue and not a sin.