Shaykh al-Islām—may Allah have mercy on him—said:

Section

On a “Principle” Concerning Obligations Omitted and Forbidden Acts Committed Before Embracing Islam and Repenting

The principle concerning obligations omitted by someone who was originally a non-Muslim, such as prayer, zakat, and fasting, is that, by consensus, he is not required to make them up after embracing Islam, because he did not believe them to be obligatory. This applies whether or not the message had reached him, and whether his disbelief arose from denial, obstinacy, or ignorance.

In this respect, there is no distinction between a protected non-Muslim (dhimmī) and a belligerent non-Muslim (harbī). This differs from obligations owed by a protected non-Muslim whose fulfilment is required by the covenant of protection, such as repaying debts, returning property entrusted to him, and restoring property wrongfully seized. These obligations are not waived by embracing Islam. This is not because he had accepted them as binding before embracing Islam.

As for someone who is strictly a belligerent non-Muslim, he had undertaken no obligation toward the Muslims, whether concerning acts of worship or other rights. He is therefore not required to discharge any past obligations, whether duties owed to Allah or rights owed to Muslims, even though he would have been punished for neglecting them had he not embraced Islam. For Islam wipes out what came before it.