It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that a Jew passed by the Messenger of Allah (peace and blessings be upon him) while he (peace and blessings be upon him) was narrating hadiths to his companions. The Quraysh said to the Jew: O Jew! This man considers himself a prophet. He said: I will ask him about something that only a prophet knows. So he came and sat down, then he said: O Muhammad! From what is man created? He (peace and blessings be upon him) said: O Jew! Man is created from both the man and the woman, from the sperm of the man and the sperm of the woman. The man's sperm is thick, from which bones and muscles are made, and the woman's sperm is thin, from which flesh and blood are made. The Jew said: The people before you also used to say the same.