The Book of Oaths
27/5. Chapter:
Saying: "If Allah wills" when swearing oaths and at other times
Sahih Muslim
وَحَدَّثَنِيهِ سُوَيْدُ بْنُ سَعِيدٍ، حَدَّثَنَا حَفْصُ بْنُ مَيْسَرَةَ، عَنْ مُوسَى بْنِ عُقْبَةَ، عَنْ أَبِي، الزِّنَادِ بِهَذَا الإِسْنَادِ مِثْلَهُ . غَيْرَ أَنَّهُ قَالَ " كُلُّهَا تَحْمِلُ غُلاَمًا يُجَاهِدُ فِي سَبِيلِ اللَّهِ ".
This hadith has been narrated on the authority of Abu Zinad with the same chain of transmitters with a variation of (these words): " Every one of them giving birth to a child, who would have fought in the cause of Allah."
Reference : Sahih Muslim 1654fIn-book reference : Book 27, Hadith 37USC-MSA web (English) reference : Book 15, Hadith 4070