Continuation of the explanation of the hadith of al-Nu'man ibn Sam'an al-Ansari: (… and sin is that which nags in your soul and which you dislike for people to see).

The Shaykh : Similarly, when he was asked about sin, he answered in the same style as before, saying: What does "nags in the soul" mean? In another narration of the hadith, it is: It means the soul goes back and forth with its owner, wondering, "Is this matter good or not good? Is it permissible or not permissible? Is it disliked or is there nothing wrong with it?" Amidst all these questions the Muslim asks himself, he finds in his soul a sense of discomfort and aversion to doing that thing which nags in his soul. This is sin, and it is even more so . Is this the only sin? No. Allah the Exalted said in describing the servants of the Most Merciful: So sin is committing all the sins that Allah (Mighty and Majestic) has forbidden, for which their doer deserves punishment, each according to his degree. Why do we see the Messenger (peace be upon him) here explaining sin as that which nags in the soul? This is also to draw attention to the importance of this type of what nags in the soul. Therefore, the general sin is known to all people: do not steal, do not commit unlawful sexual intercourse, do not cheat, and so on. There is no one, even if he is the most ignorant of people regarding Islam and the most sinful in his actions, who does not know that all these matters are sin and that their doer deserves to enter the Fire because of them. But the questioner needed to be informed of another type of sin that does not occur to the minds of many good Muslims, let alone others. So he (peace be upon him) said: . This hadith explaining sin actually aligns with other types of hadiths of the Messenger (may Allah's prayers and blessings be upon him), for example: the hadith of al-Nu'man ibn Bashir, who said: I heard the Messenger of Allah (may Allah's prayers and blessings be upon him) say: . These doubtful matters are the ones that nag in the soul; a person does not know whether this is from the lawful or the forbidden. So the complete Muslim in his religion and his character is the one who leaves what nags in his soul from what he doubts is permissible or lawful in Islam. Similarly, this hadith resembles another hadith narrated by al-Hasan ibn 'Ali ibn Abi Talib (may Allah be pleased with them both), who said: The Messenger of Allah (may Allah's prayers and blessings be upon him) said: And it is authentic: . Leave the thing you doubt for the thing you do not doubt.
This hadith, which explains sin here, actually resolves many matters that people ask about, especially in the present age. Take, for example, canned goods, canned meat, butter, and cheese made in the West, in the lands of disbelief and misguidance, where . There is much questioning from men and women: Is it permissible to eat these cans, this canned meat? Is it permissible to buy this meat that comes frozen, a single piece of a slaughtered animal? Is it permissible to eat it or not? There is much questioning about such issues. Similarly, the butter and cheese contain animal fats… and the slaughtered animal contains fats, for example from pork, or does it not? These are matters that are not easy for every person of obligation to know the facts of the chemical composition of these things, and a person is not able to know whether these animals were slaughtered with a lawful slaughter or killed in a way that makes their ruling like "fataisah" (carrion). Some people try to find out, but not everyone is like that.