Sahih al-Bukhari 3125
صحيح البخاري#3125SahihNarrated Aslam:`Umar said, "Were it not for those Muslims who have not come to existence yet, I would have distributed (the land of) every town I conquer among the fighters as the Prophet (ﷺ) distributed the land of Khaibar
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: 57:34