Sulayman bin Dawud said, "Tonight I will visit a hundred wives, and each of them will bear a son who will fight in the cause of Allah." He did not say, "If Allah wills." Yet none of them gave birth except one, who bore half a person.The Messenger of Allah ﷺ said, "Had he said, 'If Allah wills,' a hundred sons would have been born to him, every one of them fighting in the cause of Allah."
حدثنا هشيم عن هشام عن ابن سيرين
قال سليمان بن داود أطوف الليلة على مائة امرأة تلد كل واحدة منهن غلاما يقاتل في سبيل الله ولم يستثن فما ولدت إلا واحدة منهن بشق إنسان قال قال رسول الله ﷺ لو استثنى لولد له مائة غلام كلهم يقاتل في سبيل الله
Its isnad is sahih. Hisham is Ibn Hassan. Ibn Sirin is Muhammad. Bukhari and Muslim both narrated the hadith through multiple routes. See Fath al-Bari 6:26, 330, and 11:460, 524, and 13:377, and Muslim 2:17–18. Al-Hafiz noted this Musnad narration in Fath al-Bari 6:330.His saying "he did not make an exception" means he did not say, "If Allah wills." His saying "with half a man" means with half of him. What is meant, and Allah knows best, is that he is weak, unable to fight, and of no use at all.