Sunan an-Nasa'i 1149
سنن النسائي#1149SahihIt was narrated that Abdullah said:"The Messenger of Allah (ﷺ) used to say the takbir every time he got up, went down, stood and sat. Abu Bakr, 'Umar, and 'Uthman (did likewise)
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
In-book reference: 12:121