Umm al-Mu'mineen Aisha (may Allah be pleased with her) says that the Prophet Muhammad (peace and blessings be upon him) sent a marriage proposal to Abu Bakr al-Siddiq (may Allah be pleased with him) for me. Abu Bakr al-Siddiq (may Allah be pleased with him) said, "I am your brother." The Prophet (peace and blessings be upon him) replied, "You are my brother in Allah's religion and His Book, and she (Aisha) is lawful for me."