[16].Surah An-Nahl [The Bees] : Ayat 28-29

Ayat 28. "Those whose lives the angels take while they are doing wrong to themselves (by disbelief and by associating partners in worship with Allah and by committing all kinds of crimes and evil deeds)." Then, they will make (false) submission (saying): "We used not to do any evil." (The angels will reply): "Yes! Truly, Allah is All-Knower of what you used to do.

Ayat 29. "So enter the gates of Hell, to abide therein , and indeed, what an evil abode will be for the arrogant." 

Hazrat An-Nu`man bin Bashir (May Allah be pleased with them) reported: Messenger of Allah   [SAWW](PBUH) said, "What is lawful is clear and what is unlawful is clear, but between them are certain doubtful things which many people do not know. So he who guards against doubtful things keeps his religion and his honour blameless. But he who falls into doubtful things falls into that which is unlawful, just as a shepherd who grazes his cattle in the vicinity of a pasture declared prohibited (by the king); he is likely to stray into the pasture. Mind you, every king has a protected pasture and Allah's involved limits is that which He has declared unlawful. Verily, there is a piece of flesh in the body, if it is healthy, the whole body is healthy, and if it is corrupt, the whole body is corrupt. Verily, it is the heart.''  [Muslim Book 10, Chapter 41, Hadith # 3882]. 

Lesson : as mentioned above in Surah An-Nahl Ayat 28.committing all kinds of crimes and evil deeds). There are such meeting-points between what is permissible and what is not permissible in the matter of religion of which the majority of people are ignorant. If man abstains from them, it means that he is keeping his duty to Allah. Yet, if he is involved in them without caring for what is allowable or unallowable, he may be supposed to have out stepped the Divine limits. Businessmen and traders are particularly warned here to avoid things of dubious nature and are urged to adopt only that pattern which is lawful. Another important point underlying this Hadith concerns the heart. Its purity or impurity directly affects the human conduct in a good or bad way. It is, therefore, absolutely necessary to cleanse the heart of all wiles and impurities, and this is not possible without sound Faith and consciousness of Allah.