Verily, the lawful is clear, and the unlawful is clear

The Prophet (may Allah's peace and blessings be upon him) explains a general rule in matters and that they fall under three categories in the Shariah: clearly lawful matters, clearly unlawful matters, and doubtful matters with the rulings on whether they are illegal or lawful being unclear and unknown to many people.

So, whoever abandons those suspicious matters keeps his religion safe by avoiding falling into the unlawful and keeps his honor safe from people's criticism of him for engaging in such doubtful things. Whoever does not avoid doubtful matters risks falling into the unlawful or being maligned by people.

The Messenger (may Allah's peace and blessings be upon him) provided a parable to demonstrate the condition of a person who engages in doubtful matters, saying that he is like a shepherd who grazes his cattle close to a piece of land protected by its owner; so, his cattle are likely to pasture in this protected land, given its proximity. Likewise, he who engages in a suspicious matter draws near to the unlawful and is likely to fall into it.

Then, the Prophet (may Allah's peace and blessings be upon him) informed that there is a piece of flesh in the body, namely the heart, and when it is sound, the whole body is sound, and if it is corrupt, the entire body becomes corrupt.