Is it permissible to congratulate a Kitābī wife on her religious holidays?

A Muslim is not permitted to congratulate disbelievers on their religious holidays, whether the congratulator is a spouse or otherwise. This is because the act of congratulating them on these holidays is fundamentally prohibited. Ibn al-Qayyim mentioned that congratulating them on their specific rites of disbelief is forbidden by consensus, and that even if theayer is safe from disbelief, it is still among the prohibited acts. Indeed, it is a greater sin in the sight of Allah than congratulating someone on drinking alcohol or killing a soul.