To be called Abu Turab, though one already has another Kunyah name

Narrated Sahl bin Sad:

The most beloved names to 'Ali was Abu Turab, and he used to be pleased when we called him by it, for none named him Abu Turab (for the first time), but the Prophet. Once 'Ali got angry with (his wife) Fatima, and went out (of his house) and slept near a wall in the mosque. The Prophet came searching for him, and someone said, "He is there, Lying near the wall." The Prophet came to him while his ('Ali's) back was covered with dust. The Prophet started removing the dust from his back, saying, "Get up, O Abu Turab!"

حَدَّثَنَا خَالِدُ بْنُ مَخْلَدٍ، حَدَّثَنَا سُلَيْمَانُ، قَالَ حَدَّثَنِي أَبُو حَازِمٍ، عَنْ سَهْلِ بْنِ سَعْدٍ، قَالَ إِنْ كَانَتْ أَحَبَّ أَسْمَاءِ عَلِيٍّ ـ رضى الله عنه ـ إِلَيْهِ لأَبُو تُرَابٍ، وَإِنْ كَانَ لَيَفْرَحُ أَنْ يُدْعَى بِهَا، وَمَا سَمَّاهُ أَبُو تُرَابٍ إِلاَّ النَّبِيُّ ﷺ غَاضَبَ يَوْمًا فَاطِمَةَ فَخَرَجَ فَاضْطَجَعَ إِلَى الْجِدَارِ إِلَى الْمَسْجِدِ، فَجَاءَهُ النَّبِيُّ ﷺ يَتْبَعُهُ، فَقَالَ هُوَ ذَا مُضْطَجِعٌ فِي الْجِدَارِ فَجَاءَهُ النَّبِيُّ ﷺ وَامْتَلأَ ظَهْرُهُ تُرَابًا، فَجَعَلَ النَّبِيُّ ﷺ يَمْسَحُ التُّرَابَ عَنْ ظَهْرِهِ يَقُولُ " اجْلِسْ يَا أَبَا تُرَابٍ ".