Description of bowing (Rukū‘):
When the Prophet (may Allah bless him and give him peace) finished his recitation, he would remain silent for a short while. Then he would raise his hands as mentioned in the explanation of the opening Takbir (“Takbir al-Ihram”), and saying “Allahu Akbar” he would go into bowing.
In the hadith that has been mentioned: “When you stand for prayer, say the Takbir, then recite whatever you can from the Qur’an, then bow until you are at ease in your bowing.”
In the state of bowing, the Prophet (may Allah bless him and give him peace) would place both palms of his hands on his knees, and he instructed the people to do the same: “Place both of your hands firmly on your knees as if you are holding them, and spread out your fingers.”
He also said: “When you bow, place both your palms on your knees, and spread your fingers, and remain until all your joints settle in their places.”
The Prophet (may Allah bless him and give him peace) would keep his elbows away from his sides during bowing. When he bowed, he would straighten his back so evenly that if water were poured on it, it would remain level. And in bowing, you should neither lower your head nor raise it high, but keep it aligned with your back.