Sunan an-Nasa'i 1332
سنن النسائي#1332SahihIt was narrated that Al-Bara' bin 'Azib said:"I watched the Messenger of Allah (ﷺ) when he prayed, and I noticed that his standing, his bowing, his standing up after bowing, his prostration, his sitting between the two prostrations and his sitting between the taslim and departing were almost the same in length
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih Muslim
In-book reference: 13:154