Mishkat al-Masabih 30 Fine Qualities كتاب المناقب 122

وَعَن عَليّ قَالَ: كَانَتْ لِي مَنْزِلَةٌ مِنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَمْ تَكُنْ لِأَحَدٍ مِنَ الْخَلَائِقِ آتِيهِ بِأَعْلَى سَحَرٍ فَأَقُولُ: السَّلَامُ عَلَيْكَ يَا نَبِيَّ اللَّهِ فَإِنْ تَنَحْنَحَ انْصَرَفْتُ إِلَى أَهْلِي وَإِلَّا دَخَلْتُ عَلَيْهِ. رَوَاهُ النَّسَائِيُّ

“Ali said: I had a position in relation to God’s messenger which no other creature had. I would come to him at the break of day and say, “Peace be upon you, prophet of God.” If he then cleared his throat I went off to my family, otherwise I entered. Nasa’i transmitted it.