Sunan an-Nasa'i 267
It was narrated that Huthaifah said:
"When the Messenger of Allah (ﷺ) met a man from among his Companions, he would shake hands with him and supplicate for him. I saw him one day in the early morning, and I tried to avoid him, then I came to him later in the day. He said: 'I saw you but you were avoiding me.' I said: 'I was Junub and I was afraid that you would touch me.' The Messenger of Allah (ﷺ) said: 'The Muslim is not made impure (Najis).'"
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا جَرِيرٌ، عَنِ الشَّيْبَانِيِّ، عَنْ أَبِي بُرْدَةَ، عَنْ حُذَيْفَةَ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا لَقِيَ الرَّجُلَ مِنْ أَصْحَابِهِ مَاسَحَهُ وَدَعَا لَهُ - قَالَ - فَرَأَيْتُهُ يَوْمًا بُكْرَةً فَحِدْتُ عَنْهُ ثُمَّ أَتَيْتُهُ حِينَ ارْتَفَعَ النَّهَارُ فَقَالَ ‏"‏ إِنِّي رَأَيْتُكَ فَحِدْتَ عَنِّي ‏"‏ ‏.‏ فَقُلْتُ إِنِّي كُنْتُ جُنُبًا فَخَشِيتُ أَنْ تَمَسَّنِي ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ إِنَّ الْمُسْلِمَ لاَ يَنْجُسُ ‏"‏ ‏.‏