The Prophet ﷺ would say the takbir as he descended.
حدثنا عبد الله بن منير المروزي قال سمعت علي بن الحسن قال أخبرنا عبد الله بن المبارك عن ابن جريج عن الزهري عن أبي بكر بن عبد الرحمن
أن النبي ﷺ كان يكبر وهو يهوي
No references are available.
Agreed upon [by Bukhari and Muslim]. Muslim narrated it in the Book of Prayer, Chapter on Establishing the Takbir at Every Lowering and Rising in Prayer, etc., hadith no. 392, from the hadith of Ibn Jurayj, and Bukhari, hadith no. 803, from the hadith of Zuhri through him.