Sahih al-Bukhari 419

Arabic

حَدَّثَنَا يَحْيَى بْنُ صَالِحٍ، قَالَ حَدَّثَنَا فُلَيْحُ بْنُ سُلَيْمَانَ، عَنْ هِلاَلِ بْنِ عَلِيٍّ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ صَلَّى بِنَا النَّبِيُّ صلى الله عليه وسلم صَلاَةً ثُمَّ رَقِيَ الْمِنْبَرَ، فَقَالَ فِي الصَّلاَةِ وَفِي الرُّكُوعِ ‏ "‏ إِنِّي لأَرَاكُمْ مِنْ وَرَائِي كَمَا أَرَاكُمْ ‏"‏‏.‏

English translation

Narrated Anas bin Malik:The Prophet (ﷺ) led us in a prayer and then got up on the pulpit and said, "In your prayer and bowing, I certainly see you from my back as I see you (while looking at you)

Reference: Sahih al-Bukhari 419, Book of Prayers (Salat). English translation by Dr. Muhammad Muhsin Khan.