Al-Kāfi - Volume 1 > Chapter on Those who use their Knowledge to Fill their Stomach and are Boastful for it
Hadith #4

4ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ الْقَاسِمِ عَنِ الْمِنْقَرِيِّ عَنْ حَفْصِ بْنِ غِيَاثٍ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ السَّلام) قَالَ إِذَا رَأَيْتُمُ الْعَالِمَ مُحِبّاً لِدُنْيَاهُ فَاتَّهِمُوهُ عَلَى دِينِكُمْ فَإِنَّ كُلَّ مُحِبٍّ لِشَيْ‏ءٍ يَحُوطُ مَا أَحَبَّ وَقَالَ (صَلَّى اللهُ عَلَيْهِ وَآلِه) أَوْحَى الله إِلَى دَاوُدَ (عَلَيْهِ السَّلام) لا تَجْعَلْ بَيْنِي وَبَيْنَكَ عَالِماً مَفْتُوناً بِالدُّنْيَا فَيَصُدَّكَ عَنْ طَرِيقِ مَحَبَّتِي فَإِنَّ أُولَئِكَ قُطَّاعُ طَرِيقِ عِبَادِيَ الْمُرِيدِينَ إِنَّ أَدْنَى مَا أَنَا صَانِعٌ بِهِمْ أَنْ أَنْزِعَ حَلاوَةَ مُنَاجَاتِي عَنْ قُلُوبِهِمْ.

4. Ali ibn Ibrahim has narrated from his father from al-Qasim from al-Minqari from Hafs ibn Ghiyath from abu ‘Abdallah (a.s.) who has said the following. “If you would find a learned person who loves the worldly gains you must not trust him in the matters of your religion because whoever would love something it will encompass and entangle him. The holy Prophet has said, ‘Allah sent wahy, revelation to David (a.s.) and told him, “Do not set between Me and yourself a learned person who loves the worldly gains lest he will bar you from the way to My love. Such people are bandits who ambush my servants who want Me. The least that I will do to such bandits is to take away from them the sweetness of their private conversations and prayers with Me.”