Riyad as-Salihin, Book 17, Hadith 1498 (In-Book)

Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah said, "A slave becomes nearest to his Rubb when he is in prostration. So increase supplications in prostrations."[Muslim].

وعن أبي هريرة رضي الله عنه أن رسول الله صلى الله عليه وسلم قال‏:‏ ‏ "‏أقرب ما يكون العبد من ربه وهو ساجد، فأكثروا الدعاء‏" ‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏

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