Imam Nawawi's 40 hadith, Chapter: An-Nawawi's 40 Hadith

The Messenger of Allah, sallallahu 'alayhi wasallam, the most truthful, the most trusted, told us: "Verily the creation of any one of you takes place when he is assembled in his mother's womb; for forty days he is as a drop of fluid, then it becomes a clot for a similar period. Thereafter, it is a lump looking like it has been chewed for a similar period. Then an angel is sent to him, who breathes the ruh (spirit) into him. This Angel is commanded to write Four decrees: that he writes down his provision (rizq), his life span, his deeds, and whether he will be among the wretched or the blessed. I swear by Allah - there is no God but He - one of you may perform the deeds of the people of Paradise till there is naught but an arm's length between him and it, when that which has been written will outstrip him so that he performs the deeds of the people of the Hell Fire; one of you may perform the deeds of the people of the Hell Fire, till there is naught but an arm's length between him and it, when that which has been written will overtake him so that he performs the deeds of the people of Paradise and enters therein." [Al-Bukhari and Muslim]