Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) was asked about suht (unlawful earnings), and he said: "It is bribery." It was said: And in judgement (what is the ruling on bribery)? He said: "That is disbelief."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9066