Sahih Muslim
The Book of Mosques and Places of Prayer — Hadith #1104
Scholarly Consensus: Sahih How we grade
حَدَّثَنِي ابْنُ نُمَيْرٍ، حَدَّثَنِي إِسْحَاقُ بْنُ مَنْصُورٍ السَّلُولِيُّ، حَدَّثَنَا هُرَيْمُ بْنُ سُفْيَانَ، عَنِ الأَعْمَشِ، بِهَذَا الإِسْنَادِ . نَحْوَهُ .
We used to greet the Messenger of Allah (ﷺ) while he was engaged in prayer and he would respond to our greeting. But when we returned from the Negus we greeted him and he did not respond to us; so we said: Messenger of Allah. we used to greet you when you were engaged in prayer and you would respond to us. He replied: Prayer demands whole attention.
Inlined from hadith #8380 — translator’s back-reference.
Hadith Grading
Each grade below reflects one scholar's assessment of the chain of transmission. The grade describes the chain, not the Prophet's words. How we grade
Scholarly Consensus: Sahih