Can a Christian join in the Ramadan fast?

What happens when a Christians chooses to join in the Ramadan fast?

The question will be: what do those Christians believe, or who is the Christian fasting to?

In Islam, disbelief invalidates good deeds. “And whosoever disbelieves rejects faith, then fruitless is his work, and in the Hereafter he will be among the losers.” [Al-Maidah 5:5]

“But if they had joined in worshipping others with Allah, all that they used to do would have been of no benefit to them.” [Al-An‘am 6:88]

Christians fasting at Ramadan

It is important to have respect for people's faith. A Christian who practices fasting or praying during Ramadan while not a Muslim is considered invalid, as it requires being Muslim to participate in the practice of Ramadan.

A Christian fasting during Ramadan must first believe in Prophet Muhammad as the messenger of Allah and enter Islam. If they do so, they are required to pray, fast, give zakah, and perform hajj, all of which are essential aspects of Islam.

This act of worship is not beneficial and it's a waste as it contradicts the condition of being a Muslim.

The person must commit to Islam by directing their worship to Allah alone and giving up their Christian belief in the Messiah as the son of God and the Trinity.

In conclusion, it contradicts the Christian faith to fast the Ramadan fast. If a Christian is fasting separately during that period and not, in a sense, ‘joining the Muslims', then it works, but it is not the Ramadan fast.