The people used to offer the prayer with the Prophet (ﷺ) with their waist-sheets tied round their necks because of the shortness of the sheets and the women were ordered not to lift their heads till the men had sat straight.
Sahih al-Bukhari Book 21, Hadith 19
← Previous Hadith The Prophet (ﷺ) said, "Whenever anyone of you is in prayer, he is speaking in private to his Lord and so he should neither spit in front of him nor on his right side but to his left side under his left foot."

Sahih al-Bukhari Book 21, Hadith 18 Next Hadith → I used to greet the Prophet (ﷺ) while he was in prayer and he would return my greeting, but when we returned (from Ethiopia) I greeted the Prophet (while he was praying) but he did not return the greeting, and (after finishing the prayer) he said, "In the prayer one is occupied (with a more serious matter)."

Sahih al-Bukhari Book 21, Hadith 20