Mishkat al-Masabih 82

Ibn Mas'ud said that God’s messenger who spoke the truth and whose word was believed told them the following: The constituents of one of you are collected for forty days in his mother’s womb in the form of a drop, then they become a piece of congealed blood for a similar period, then they become a lump of flesh for a similar period. Then God sends to him an angel with four words who records his deeds, the period of his life, his provision, and whether he will be miserable or blessed: thereafter He breathes the spirit into him. By Him other than whom there is no god, one of you will do the deeds of those who go to paradise so that there will be only a cubit between him and it, then what is decreed will overcome him so that he will do the deeds of those who go to hell and will enter it; and one of you will do the deeds of those who go to hell so that there will be only a cubit between him and it, then what is decreed will overcome him so that he will do the deeds of those who go to paradise and will enter it. (Bukhari and Muslim.)