Sahih al-Bukhari 2819
صحيح البخاري#2819SahihNarrated Abu Huraira: Allah's Messenger (ﷺ) said, "Once Solomon, son of David said, '(By Allah) Tonight I will have sexual intercourse with one hundred (or ninety-nine) women each of whom will give birth to a knight who will fight in Allah's Cause.' On that, a companion (angel) said to him, "(Say) Allah willing", but he did not say, "Allah willing." Therefore only one of those women conceived and gave birth to a half-man. By Him in Whose Hands Muhammad's life is, if he had said, "Allah willing', (he would have begotten sons) all of whom would have been knights striving in Allah's Cause
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 56:35