Without doubt, differing openly leads to differing inwardly, just as agreeing openly leads to agreeing inwardly. Thus, the Prophet ﷺ prohibited resembling disbelievers, in many Texts, because agreeing with them openly leads to agreeing with them inwardly, and differing with them openly leads to abandoning them inwardly. The same can be said for differences and agreements with opponent Muslims who are innovators and disobedient to Allaah. It is reported in Muslim’s Ssaheeh,
“Straighten your rows and do not differ, for your hearts would differ!” (Muslim 432)
This is proof for the fact that differing openly drags a person into differing inwardly, by necessity.