It was narrated from Ibn 'Abbas that:
The Prophet said: "There will be some people among my Ummah (nation) who will gain knowledge of the religion, and they will recite Qur'an, and will say: 'We come to the rulers so that we may have some share of their worldly wealth, and we will make sure that our religious commitment is not affected,' but that will not be the case. Just as nothing can be harvested from the Qatad except thorns, so nothing can be gained from being close to them except (sins).'" (Da'if)(One of the narrators) Muhammed bin As-Sabbah said: "It is as if he meant, 'except sins'."
English reference: Vol. 1, Book 1, Hadith 255
Arabic reference: Book 1, Hadith 264