What is the ruling and reward for a man who raises his wife's daughter from another man?

The daughter of a man's wife is called his stepdaughter (rabībah), and she is considered one of his unmarriageable kin (mahārim). It is desirable for her mother's husband to raise her. He will receive reward according to the child's situation. If she is an orphan, his reward is immense, based on the Prophet's (peace and blessings be upon him) saying: "I and the guardian of an orphan will be in Paradise like these two," and his saying: "The best house among Muslims is a house in which there is an orphan who is treated well." If she is not an orphan, he will receive reward according to her needs and what he expends in raising her.