Sayyiduna Nu'man bin Bashir (may Allah be pleased with him) says that he heard the Messenger of Allah (peace and blessings be upon him) say: "The lawful is clear and the unlawful is clear, and between them are doubtful matters which many people do not know. Whoever guards himself against the doubtful matters has safeguarded his honour and his religion, and whoever falls into the doubtful matters falls into the unlawful. It is like a shepherd who grazes (his animals) around a protected pasture: he is close to (his animals) entering it. Moreover, every king has a protected pasture; beware, the protected pasture of Allah is the things He has made unlawful. Beware, in the body there is a piece of flesh: when it is sound, the whole body is sound, and if it is corrupt, the whole body is corrupt. Beware, it is the heart."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10400
Sayyiduna Nu'man bin Bashir (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "The lawful is clear and the unlawful is clear, and between them are doubtful matters. Whoever leaves what is doubtful to him will all the more leave what is clear to him, and whoever ventures upon what he is in doubt about is close to falling into what is clear to him (as unlawful). Sins are the protected pasture of Allah, and whoever grazes (his animals) around the protected pasture is close to (their) entering it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10401
Sayyiduna Abu Hurayrah (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "A time will certainly come upon the people when a man will not care whether he acquired wealth by lawful means or unlawful."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10402