How can one understand the hadith: "Do not accompany anyone but a believer, and let no one eat your food but one who is pious" in the case of helping Muslims who commit forbidden acts, such as drinking alcohol and fornication, by providing them with money, food, and shelter, while inviting them to righteousness and seeking their reform, and for how long can this assistance be continued?

The hadith: "Do not accompany except a believer, and let no one eat your food except a pious person," means to avoid companionship, mixing, and commensality that have no legitimate religious benefit, due to their negative impact on one's religion and character.

However, it is permissible to mix with non-believers and invite them to eat, if the Muslim intends thereby to win their hearts and incline them towards their دعوتهم [da‘wah - call to Islam] and advice, or to show kindness to them and meet their needs. This is permissible even with non-Muslims.

The intent of the Prophet's saying: "Let no one eat your food except a pious person," is to invite the pious to eat, and not to deprive the impious of kindness. Kindness encompasses both the pious and the impious, especially if it influences the impious.

When showing kindness, one should not give a person what would help them commit disobedience, such as using the money given to them for disobedience, or saving their own money for acts of disobedience relying on assistance.