"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)."  

كَانَ رَسُولُ اللَّهِ ﷺ يُكَبِّرُ فِي كُلِّ رَفْعٍ وَوَضْعٍ وَقِيَامٍ وَقُعُودٍ وَأَبُو بَكْرٍ وَعُمَرُ وَعُثْمَانُ ؓ  

"When the Messenger of Allah ﷺ stood to pray, he said the takbir, when he (started), then he said the takbir when he bowed, then he said: 'Sami Allahu liman hamidah (Allah hears the one who praises Him)', when he stood up from bowing. Then he said when he was standing: 'Rabbana lakal-hamd.' Then he said the takbir when he went down in prostration, then he said the takbir when he raised his head, and he did that throughout the entire prayer until he finished it, and he said the takbir when he stood up after the first two rak'ahs, after sitting."  

أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ يَقُولُ كَانَ رَسُولُ اللَّهِ ﷺ إِذَا قَامَ إِلَى الصَّلاَةِ يُكَبِّرُ حِينَ يَقُومُ ثُمَّ يُكَبِّرُ حِينَ يَرْكَعُ ثُمَّ يَقُولُ سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ حِينَ يَرْفَعُ صُلْبَهُ مِنَ الرَّكْعَةِ ثُمَّ يَقُولُ وَهُوَ قَائِمٌ رَبَّنَا لَكَ الْحَمْدُ ثُمَّ يُكَبِّرُ حِينَ يَهْوِي سَاجِدًا ثُمَّ يُكَبِّرُ حِينَ يَرْفَعُ رَأْسَهُ ثُمَّ يُكَبِّرُ حِينَ يَسْجُدُ ثُمَّ يُكَبِّرُ حِينَ يَرْفَعُ رَأْسَهُ ثُمَّ يَفْعَلُ ذَلِكَ فِي الصَّلاَةِ كُلِّهَا حَتَّى يَقْضِيَهَا وَيُكَبِّرُ حِينَ يَقُومُ مِنَ الثِّنْتَيْنِ بَعْدَ الْجُلُوسِ