(47) باب الْجَمَاعَةُ لِلْفَائِتِ مِنَ الصَّلاَةِ
It was narrated that Anas said:
"The Messenger of Allah (ﷺ) turned to face us when he stood up to pray, before he said Takbir, and said: 'Make your rows straight and fill the gaps, for I can see you from behind my back."'
Reference: Sunan an-Nasa'i 845
In-book reference: Book 10, Hadith 69
English translation: Vol. 1, Book 10, Hadith 846