When the Messenger of Allah (may Allah's peace and blessings be upon him) got up for prayer, he would say Takbīr when he stands. Then he would say Takbīr when he bows. Then he would say: "Allah hears the one who praised Him" when he raises his back from bowing
Authentic hadithعن أبي هُرَيْرَةَ رضي الله عنه قال: كان رسول الله صلى الله عليه وسلم إذا قام إلى الصلاة يُكَبِّرُ حين يقوم، ثم يُكَبِّرُ حين يركع، ثم يقول: سَمِعَ اللَّه لِمَنْ حَمِدَهُ، حين يَرْفَعُ صُلْبَهُ من الرَّكْعَةِ، ثم يقول وهو قائم: ربنا ولك الحمد، ثم يُكَبِّرُ حين يَهْوِي، ثم يُكَبِّرُ حين يَرْفَعُ رأسه، ثم يُكَبِّرُ حين يَسْجُدُ، ثم يُكَبِّرُ حين يَرْفَعُ رأسه، ثم يفعل ذلك في صلاته كلها حتى يقضيها، ويُكَبِّرُ حين يقوم من الثِّنْتَيْنِ بعد الجلوس، ثم يقول: أبو هريرة «إني لأشَبَهُكم صلاة برسول الله صلى الله عليه وسلم ».
Abu Hurayrah (may Allah be pleased with him) reported: 'When the Messenger of Allah (may Allah's peace and blessings be upon him) got up for prayer, he would say Takbīr when he stands. Then he would say Takbīr when he bows. Then he would say: "Allah hears the one who praised Him" when he raises his back from bowing. Then he would say while standing: "O Lord, to you belongs the praise!" Then he would say Takbīr when he goes down (to prostrate) and would say Takbīr when he raises his head. Then he would say Takbīr when he prostrates himself, then he would say Takbīr on raising his head. He would do that throughout the whole prayer until he completes it. He would also say Takbīr when he gets up at the end of the two Rak‘ahs Abu Hurayrah then said: ''My prayer has the closest resemblance to the prayer of the Messenger of Allah (may Allah's peace and blessings be upon him).''
Explanation
Throughout prayer one glorifies Allah with words and actions. This noble Hadīth explains the emblem of prayer: Allah's grandeur and greatness. This was made its symbol only because prayer itself was prescribed for the exaltation and glorification of Allah. When starting the prayer, one says the Takbīr al-Ihrām while standing up. After one recites some Qur'an and bows, one says "Allah Akbar". Then when rising from bowing, one says ''Allah hears the one who praised Him!'' Then one stands up again, praises Allah and glorifies Him while standing. When going down for prostration, one says "Allah Akbar" and does so when rising one's head from prostration. The procedure is observed throughout the prayer, until one finishes. When standing up from the first Tashahhud, one says "Allah Akbar". In taking up a new posture in prayer, one says Takbīr except when rising from bowing.
Source · Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).