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.

Sayyiduna Abdullah (may Allah be pleased with him) also narrates that the Messenger of Allah (peace and blessings be upon him) said: Surely, the sperm remains in its state for forty days, there is no change in it. When forty days pass, it becomes a clot of congealed blood. Then after forty days, it becomes a lump of flesh. Then after forty days, bones are formed. So when Allah Almighty intends to complete its creation, He sends an angel towards it. The angel responsible for this task says: O my Lord! Is it male or female? Fortunate or unfortunate? Short in stature or tall? Deficient in creation or excessive in creation? Also, its sustenance and death? And is it healthy or sick? So all these things are written down. One of the people said: If all this matter has already been decided, then what is the point of action? The Prophet (peace and blessings be upon him) said: You should act, for every person will be directed towards that for which he was created.