Ibrahim is my cousin, he told me he committed many sins like not praying, not fasting for a long period of time. he used to steal the people. He also did some bad things like fornicating and using drugs. I used to preach him in Islam; one day surprisingly he said I want to start the prayer, I became very happy and i told to take a bath and wudhu and follow me to the mosque. The next day I told him I am going to follow Jamacatu Tabligh for da’wa and I want him to follow me, he followed me. mashaAllah he is very good Muslim; then he started to worry about his previous sins, and he started to ask me many questions. I finally told him I can’t answer, ask sheikh. Then he told sheikh about his story; and asked if his previous sins will be forgiven, the sheikh said to him you repented and your previous sins will be forgiven in-shaAllah but you need to ask forgiveness the people you stole, then he said I can’t because I know they will not forgive me. The sheikh said you must ask forgiveness. Then he decided to become kafir and then become Muslim instantly because his previous sins will be forgiven. Then he insulted the religion and the angels and instantly pronounced the Shahadah; he came to me and told me about what bad things he has done and he asking if he became apostate and came back to fold of Islam instantly whether his previous sins particularly the theft will be forgiven? Please help…
بسم الله الرحمن الرحيم
In the question mentioned above if Ibrahim (your cousin) has insulted religion and the angels and thereafter read Kalimah Shahadah sincerely i.e. he became Muslim wholeheartedly after being apostatized then now he is a Muslim. And when he has repented from his sins then his sins are forgiven. The sin of theft is also forgiven by taubah but it is mandatory for him to return the stolen goods to its owner.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.