Riyad as-SalihinChapter 8Hadith 417
Full Sharh — Riyad as-Salihin 417
وعن أبي هريرة رضي الله عنه قال قال رسول الله صلى الله عليه وسلم: "وسطوا الإمام، وسدوا الخلل" ((رواه أبو داود)).
English Translation
Abu Hurairah (May Allah be pleased with him)reported:: The Messenger of Allah (ﷺ) said, "Let the Imam stand in the middle (so that those praying behind him should be standing both on his right and his left) and close the gaps.".
Source
Riyad as-Salihin(رياض الصالحين)
The Book of Virtues
Hadith Number
417