The Book of Destiny

Sahih Muslim

Verily your creation is on this wise. The constituents of one of you are collected for forty days in his mother's womb in the form of blood, after which it becomes a clot of blood in another period of forty...

Sahih Muslim

" The creation of any one of you is like this that (semen) is collected in the womb of the mother for forty nights," and in the hadith transmitted on the authority of Shu'ba (the words are):" Forty nights and...