Giving an example of beneficial knowledge: The hadith of Abu Hurayrah regarding the three men who are the first to be cast into the Fire

And what is sufficient for me now from those hadiths is a hadith narrated by Imam Muslim in his Sahih from the hadith of Abu Hurayrah (may Allah be pleased with him): that he was in one of the gatherings of Mu'awiyah ibn Abi Sufyan (may Allah be pleased with him), and he was asked to narrate to them the hadith of the Prophet (peace and blessings be upon him) concerning who are the first to be cast into the Fire on the Day of Resurrection. So he prepared to narrate this hadith that was requested of him, but because of the terror the hadith caused in his heart, he fainted. And when he came to, and perhaps in the hadith I am not certain whether he came to until he was sprinkled with water, the important thing is that when he came to, he prepared to narrate it again, but he fainted. And so it was three times. Then he gathered his resolve and his soul and said: The Messenger of Allah (peace and blessings be upon him) said: This first man of the three who are cast into the Fire on the Day of Resurrection. We ask Allah (Mighty and Majestic) to protect us from the Fire and to make us among these three: the scholar who does not act upon his knowledge, the rich man who spends his wealth for the show of people, and the mujahid. So this scholar, in whom it was expected that he would be in the high ranks, and yet he is in the lowest depth of the Fire. Why? Because he taught people and spread his knowledge, but he did not seek thereby the Face of Allah. Therefore, sincerity in acts of worship is the fundamental principle in them. And so Allah the Exalted said: So whoever does a deed not for the Face of Allah has associated others with Allah in it, like this scholar who spread his knowledge. Why? So that people would say about him, "So-and-so is a scholar." It was said to him on the Day of Resurrection: "This is what you prepared for, and what you aimed for and sought, you have attained. People said, 'So-and-so is a scholar.' Take him to the Fire, because he was not sincere to Allah in his knowledge." Also, this mujahid, when he fought in the cause of Allah, it appeared so, but he did not intend thereby the Face of Allah, and he did not intend thereby that the word of Allah be the supreme, as came in the hadith of Abu Musa al-Ash'ari (may Allah be pleased with him): This mujahid, the second man of the three, only fought so that people would say, "So-and-so is brave," "So-and-so is a hero." And he also attained what he aimed for, which is that people would say about him that he is a hero. So he deserved to enter the Fire due to his lack of sincerity in his jihad in the cause of Allah.