" 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 forty days." And in the hadith transmitted on the authority of Jarir and 'Isa (the words are):" Forty days."
فِي حَدِيثِ وَكِيعٍ إِنَّ خَلْقَ أَحَدِكُمْ يُجْمَعُ فِي بَطْنِ أُمِّهِ أَرْبَعِينَ لَيْلَةً وَقَالَ فِي حَدِيثِ مُعَاذٍ عَنْ شُعْبَةَ أَرْبَعِينَ لَيْلَةً أَرْبَعِينَ يَوْمًا وَأَمَّا فِي حَدِيثِ جَرِيرٍ وَعِيسَى أَرْبَعِينَ يَوْمًا