Ṣaḥīḥ Muslim
4. The Book of Prayers
(27) Chapter:
The Command to Be Calm During the Prayer
And the Prohibition of Gesturing with One's Hand and Raising It When Saying the Salām;
And Completing the First Rows, Aligning In Them,
And the Command to Come Together
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Jabir b. Samura reported:
The Messenger of Allah (ﷺ) came to us and said:
"- How is it that I see you lifting your hands like the tails of headstrong horses? Be calm in prayer."
He (the narrator) said: He then again came to us and saw us (sitting) in circles. He said:
"- How is it that I see you in separate groups?"
He (the narrator) said: He again came to us and said:
"- Why don't you draw yourselves up in rows as angels do in the presence of their Lord?"
We said:
- Messenger of Allah, how do the angels draw themselves up in rows in the presence of their Lord?
He (the Holy Prophet) said:
"- They make the first rows complete and keep close together in the row."
Reference = Ṣaḥīḥ Muslim 430 a
In-book reference = Book 4, Hadith 130