Sunan Abi Dawud 4292
سنن أبي داود#4292SahihDhu Mikhbar said:I heard the Messenger of Allah (ﷺ) say: you will make a secure peace with the Byzantines, then you and they will fight an enemy behind you, and you will be victorious, take booty, and be safe. You will then return and alight in a meadow with mounds and one of the Christians will raise the cross and say: The cross has conquered. One of the Muslims will become angry and smash it, and the Byzantines will act treacherously and prepare for the battle
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 39:2