Ibn ‘Abbas reported the Prophet (ﷺ) as saying, “This and that are equal,” meaning the little finger and the thumb. Bukhari transmitted it.

عَنِ ابْنِ عَبَّاسٍ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «هَذِهِ وَهَذِهِ سَوَاءٌ» يَعْنِي الخِنصرُ والإبهامَ. رَوَاهُ البُخَارِيّ