What did the Prophet Muhammad (peace be upon him) say about those who claim to be the son of someone they know is not their father?
 Narrated Sa`d:                     I heard the Prophet saying, "Whoever claims to be the son of a person other than his father, and he knows that person is not his father, then Paradise will be forbidden for him." I mentioned that to Abu Bakra, and he said, "My ears heard that and my heart memorized it from Allah's Apostle.