Sahih al-Bukhari 785
Sahih al-Bukhari · Book 10: Call to Prayers (Adhaan) · Itmam At-Takbir (i.e., to end the number of Takbir or to say the Takbir perfectly) on bowing. [See Fath Al-Bari]
Narrated Abu Salama:
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ ، قَالَ أَخْبَرَنَا مَالِكٌ ، عَنِ ابْنِ شِهَابٍ ، عَنْ أَبِي سَلَمَةَ ، عَنْ أَبِي هُرَيْرَةَ ، أَنَّهُ كَانَ يُصَلِّي بِهِمْ، فَيُكَبِّرُ كُلَّمَا خَفَضَ وَرَفَعَ، فَإِذَا انْصَرَفَ قَالَ إِنِّي لأَشْبَهُكُمْ صَلاَةً بِرَسُولِ اللَّهِ صلى الله عليه وسلم.
When Abu Huraira led us in prayer he used to say Takbir on each bowing and rising. On the completion of the prayer he used to say, "My prayer is more similar to the prayer of Allah's Messenger (ﷺ) than that of anyone of you."