Sahih al-Bukhari 598
صحيح البخاري#598SahihNarrated Jabir:`Umar came cursing the disbelievers (of Quraish) on the day of Al-Khandaq (the battle of Trench) and said, "I could not offer the `Asr prayer till the sun had set. Then we went to Buthan and he offered the (`Asr) prayer after sunset and then he offered the Maghrib prayer
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: 9:73