Hadith: The Messenger of Allah (may Allah's peace and blessings be upon him) used to start the prayer with Takbīr and then read: All praise is due to Allah, Lord of the worlds. When he bowed, he neither raised his head nor lowered it, but kept it in between

عن عائشة رضي الله عنها قالت: «كان رسول الله صلى الله عليه وسلم يَسْتَفْتِحُ الصلاةَ بالتكبير، والقراءةَ بـ«الحمد لله رب العالمين» وكان إذا ركع لم يُشْخِصْ رأسه ولم يُصَوِّبْهُ ولكن بَيْن ذلك، وكان إذا رفَع رأسَه مِن الرُّكوع لم يَسْجُدْ حتى يَسْتَوِيَ قائِما، وكان إذا رفع رأسه من السَّجْدَة لم يَسْجُدْ حتى يَسْتَوِيَ قاعدا، وكان يقول في كلِّ رَكعَتَين التَّحِيَّة، وكان يَفْرِشُ رِجْلَهُ اليُسْرى ويَنْصِبُ رِجْلَهُ اليُمْنى، وكان يَنْهَى عن عُقْبَةِ الشَّيْطَانِ، ويَنْهَى أن يفْتَرِشَ الرَّجُلُ ذِرَاعَيْهِ افتِرَاش السَّبُعِ ، وكان يَخْتِمُ الصلاة بالتَّسلِيم».
[صحيح] - [رواه مسلم]

‘Ā'ishah (may Allah be pleased with her) reported: “The Messenger of Allah (may Allah's peace and blessings be upon him) used to start the prayer with the Takbīr and then read: "All praise is due to Allah, Lord of the worldd." When he bowed, he neither raised his head nor lowered it, but kept it in between. When he raised his head from bowing, he would not prostrate until he had stood upright. When he raised his head from prostration, he would not prostrate (again) until he had sat upright. After each two units of prayer, he would recite the Tashahhud. He used to spread his left foot out and raise his right foot. He would forbid sitting in the manner of the devil and resting the forearms on the ground, as a lion does. He used to conclude the prayer with the Taslīm.
[Authentic hadith] - [Narrated by Muslim]

Explanation

In this great Hadīth, ‘Ā'ishah (may Allah be pleased with her) described how the Prophet (may Allah's peace and blessings be upon him) used to pray, in order to disseminate the Sunnah and convey the knowledge. The Prophet used to open the prayer with Takbīr of Ihrām; He would start the recitation with the opening chapter of the Qur'an (Sūrat al-Fātihah), which starts with: "All praise is due to Allah, Lord of the worlds." When he bowed from the standing position, he would neither raise nor lower his head, but he would keep it in line with his back. When he rose from bowing, he would stand upright before prostrating. When he lifted his head from prostration, he would not prostrate (again) until he had sat upright. When sitting after every two units, he would say the Tashahhud: "Salutations, prayers, and all good things are for Allah". When he sat, he would spread his left foot out and sit on it and raise his right foot. He used to forbid sitting in the manner of the devil, meaning: resting two feet on the ground with the backs of the feet on the ground and sitting on the buttocks or raising both feet and placing the buttocks between them on the ground. Likewise he forbade resting the forearms on the ground while prostrating, as lions do. Just as he opened the prayer with the Takbīr, he ended it with the Taslīm; the greeting of peace for everyone: the angels, worshipers, and the rest of Allah's servants. So every Muslim who prays should take note of these generalities in his supplications.