What he told them he could see
He asked them a question before saying it.
هَلْ تَرَوْنَ قِبْلَتِي هَا هُنَا فَوَاللَّهِ مَا يَخْفَى عَلَىَّ خُشُوعُكُمْ وَلاَ رُكُوعُكُمْ، إِنِّي لأَرَاكُمْ مِنْ وَرَاءِ ظَهْرِي
Hal tarawna qiblatī hāhunā. Fa-wa-Llāhi mā yakhfā ʿalayya khushūʿukum wa lā rukūʿukum, innī la-arākum min warāʾi ẓahrī
Do you think my face is only towards here? By Allah, neither your stillness nor your bowing is hidden from me. I see you from behind my back.
The full narration
Narrated Abu Huraira:Allah's Messenger (ﷺ) said, "Do you consider or see that my face is towards the Qibla? By Allah, neither your submissiveness nor your bowing is hidden from me, surely I see you from my back
Source
Ṣaḥīḥ al-Bukhārī · 418
Ṣaḥīḥ
- Agreed upon as authentic (al-Bukhārī / Muslim)