When does imitating disbelievers amount to disbelief, and what is the meaning of "disbelief itself" in the context of the aforementioned imitation? And what is the ruling on utilizing their actions, such as sports, and their sayings, such as proverbs and training courses, and their songs, such as children's songs?

Mere imitation of disbelievers is not an act of disbelief that expels one from the faith. Rather, it becomes disbelief if one imitates them in acts of shirk (polytheism), or in their customs and attire, provided this is done out of inclination and love for them. However, if it is done playfully, or without love for its practitioners, it is a sin and not disbelief.

Jurists have stated that merely tying the zunnar (a belt worn by dhimmis) or wearing the qallansuwat al-Majus (the headgear of the Zoroastrians) is not considered disbelief unless it is intended to imitate them in the symbols of disbelief. If that is the intention, it is disbelief. If the intention is to imitate them in the symbol of a holiday while disregarding the aspect of disbelief, then one is sinful but not a disbeliever. If there is no intention to imitate them at all, then there is no blame. Among the innovations (bid'ah) is the Muslims' conformity with Christians in their holidays by imitating their eating habits, or giving them gifts, or accepting gifts from them, or selling them what they use to assist them in their holidays.