Sunan an-Nasa'i 5210

أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَاصِمِ بْنِ كُلَيْبٍ، عَنْ أَبِي بُرْدَةَ، قَالَ قَالَ عَلِيٌّ قَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ يَا عَلِيُّ سَلِ اللَّهَ الْهُدَى وَالسَّدَادَ ‏"‏ ‏.‏ وَنَهَانِي أَنْ أَجْعَلَ الْخَاتَمَ فِي هَذِهِ وَهَذِهِ ‏.‏ وَأَشَارَ يَعْنِي بِالسَّبَّابَةِ وَالْوُسْطَى ‏.‏

It was narrated that Abu Burdah said:'Ali said: "The Messenger of Allah [SAW] said to me: 'O 'Ali, ask Allah for guidance and steadfastness,' and he forbade me from placing a ring on this one and this one' - and he pointed to his forefinger and middle finger