Abu Murrah, the freed slave of Aqil bin Abi Talib (may Allah be pleased with him), says that Umm Hani (may Allah be pleased with her) gave protection to two of her in-laws who were idolaters, and Ali (may Allah be pleased with him) set out to kill them both, saying: Why have you given protection to idolaters? Umm Hani (may Allah be pleased with her) said: Kill me before you kill them. Then she went out and said: Lock the door against him. She went to the Messenger of Allah (peace and blessings be upon him) and informed him, and he (peace and blessings be upon him) said: "O Umm Hani! That was not his right. Whomever you have granted safety, we too grant safety; whomever you have given protection, we too give protection."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18174