Hadithcore
Hadith #517290

Yahya related to me from Malik that he had heard that Abdullah ibn Abbas said, "Equanimity, gentleness, and good behaviour are one twenty-fifth of prophecy."

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، أَنَّهُ كَانَ يَقُولُ الْقَصْدُ وَالْتُّؤَدَةُ وَحُسْنُ السَّمْتِ جُزْءٌ مِنْ خَمْسَةٍ وَعِشْرِينَ جُزْءًا مِنَ النُّبُوَّةِ ‏.‏

References2 variants
Sunnah.com reference
Book 51, Hadith 17
Arabic/English book reference
Book 51, Hadith 16