Al-Kāfi - Volume 1 > Chapter on the Qualities of the Scholars
Hadith #4

4ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدِ بْنِ عِيسَى وَمُحَمَّدُ بْنُ إِسْمَاعِيلَ عَنِ الْفَضْلِ بْنِ شَاذَانَ النَّيْسَابُورِيِّ جَمِيعاً عَنْ صَفْوَانَ بْنِ يَحْيَى عَنْ أَبِي الْحَسَنِ الرِّضَا (عَلَيْهِ السَّلام) قَالَ إِنَّ مِنْ عَلامَاتِ الْفِقْهِ الْحِلْمَ وَالصَّمْتَ.

4. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad ibn ‘Isa and Muhammad ibn ‘Ism’il from al-Fadl ibn Shadhan al-Naysaburi, all from Safwan ibn Yahya from abu al-Hassan al-Rida (a.s.) who has said the following. “Of the signs of Fiqh, good understanding of religion is forbearance and quietness.”