5- Causing diseases (especially the plague) to the humans: Abu Moosa Al-Ash‘ari, may Allah be pleased with him, reported that the Prophet said, “The end of my Ummah would come through stabbing and Taa‘oon.” They said, “O messenger of Allah! We know stabbing, but what is the Taa‘oon?” He said, “Taa‘oon is the piercing of your enemies from among the Jinn, and, for you, both of them are martyrdom.” [Ahmad]

Ibn Al-Atheer said:

Piercing is like stabbing that is not deep . As for the Taa‘oon (pestilence), Avicenna described it as a poisonous substance that causes lethal tumors that infect the soft areas of the body, mostly under the armpits, behind the ear or near the tip of the nose. It is caused by bad blood that is rotten and corrupt. Its symptoms include vomiting, nausea, fainting and palpitation. You may say that the Prophet said that Taa‘oon is caused by the piercing of the Jinn, and this apparently contradicts the explanation of doctors. However, I would confirm that the Prophet has told the truth, and doctors spoke about Taa‘oon according to their rules and within the limits of their knowledge. They did not mention the piercing of the Jinns, because this is a supernatural phenomenon. Nevertheless, the symptoms that the doctors have mentioned may happen to those who become infected with Taa‘oon as a result of the piercing of the Jinns. This opinion is supported by the fact that plague usually occurs in the best seasons and in the areas that have the best weather, air, and water. If Taa‘oon were caused by bad air, then it would have infected most people and animals as well. [‘Umdat Al-Qaari Sharh Saheeh Al-Bukhari by Al-‘Ayni]

6- Seeing the ‘Awrah of the humans:

‘Ali ibn Abi Taalib, may Allah be pleased with him, reported that the Prophet said, “The screen between the eyes of Jinn and the ‘Awrahs of the members of my Ummah if one of them enters the bathroom is to say: Bismillaah (In the Name of Allah).” [At-Tirmithi]

Anas, may Allah be pleased with him, reported that the Prophet said, “Whenever the Prophet entered the lavatory, he used to say, "Allahumma inni a‘uthu bika min al-khubuthi wal khaba’ith i.e. O Allah, I seek Refuge with You from male and female devils).” [Al-Bukhari and Muslim]

Al-Munaawi said in Faydh Al-Qadeer:

This shield protects the believer from this enemy, which means that one must never forget it, because the Jinns mix with the humans all the time. So, if the human wanted to deprive the Jinn from sharing anything with him, then he should say “Bismillaah (In the Name of Allah)”. That is because the Name of Allah The Almighty seals all the provisions of the son of Adam, and it is impossible for the Jinns to remove this seal.

These were some forms of harms that the Jinns can inflict upon the humans to hurt or mislead them. However, these prohibited acts are committed only by the deviant Jinns and the devils, because the believing Jinns are as righteous and pious as the human believers are. Allah The Almighty Says (what means): {And among us are the righteous, and among us are [others] not so; we were [of] divided ways.} [Quran 72:11]

The Muslim must know that the only protection that he has against the evils of the devils is the remembrance of Allah The Almighty (Thikr), which is the stronghold of all believers.
Prophet Yahya (John), may Allah exalt his mention, said to his people, “…I command you to always remember Allah The Exalted. The example of this deed is that of a man whom the enemy is tirelessly pursuing. He takes refuge in a fortified fort. When the servant remembers Allah The Almighty, he will be resorting to the most fortified refuge from the devil.” [Ahmad]

Ibn Abu Ad-Dunya reported that Qays ibn Al-Hajjaaj said, “My devil said to me ‘I entered your body while I was as strong as a camel, but today I am as weak as a sparrow.’ I asked him about the reason and he said, ‘You melted me through reading the Book of Allah The Almighty.’”
Abu Al-Ahwas reported that ‘Abdullaah, may Allah be pleased with him, said, “The devil of the believer is skinny.”