Mishkat al-Masabih 260
He also reported the Prophet as saying, “Two greedy ones never
attain satisfaction:
he who is greedy for knowledge can never get
enough of it, and he who is greedy for worldly goods can never get
enough of them." Baihaqi transmitted the three traditions in Shu'ab
al-iman , and quoted the imam Ahmad as saying about Abu Darda''s
tradition, “This is a well-known text among the people, but it does not
have a sound isnad ."
وَعَنْهُ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: 
" مَنْهُومَانِ لَا يَشْبَعَانِ: مَنْهُومٌ فِي الْعِلْمِ لَا يَشْبَعُ مِنْهُ وَمَنْهُومٌ فِي الدُّنْيَا لَا يَشْبَعُ مِنْهَا «. رَوَى الْبَيْهَقِيُّ الْأَحَادِيثَ الثَّلَاثَةَ فِي» شُعَبِ الْإِيمَانِ " وَقَالَ: قَالَ الْإِمَامُ أَحْمَدُ فِي حَدِيثِ أَبِي الدَّرْدَاءِ: هَذَا مَتْنٌ مَشْهُورٌ فِيمَا بَين النَّاس وَلَيْسَ لَهُ إِسْنَاد صَحِيح