The Effects of Jinn on Humans, and Seeking Protection From Them

Question:

Can jinn harm man? How do we protect ourselves from them?

Answer:
No doubt, jinn can do things to harm man, sometimes things that lead to his death. Both the Sunnah and observed phenomena support this. During a battle, the Messenger of Allaah Salallaahu alayhi wasallam gave permission to one of his Companions to return to his family; that Companion was young and recently married. When he returned to his home, he saw his wife standing at their door, and he reproached her for that. She told him to go inside, and when he entered, he saw a snake on their blanket. He had a spear with him, and he pierced it into the body of the snake until it died. However, the man died at the same time, so that no one knew who died first: He or the snake. When the news of the incident reached the Messenger of Allaah Salallaahu alayhi wasallam, he forbade the killing of small sankes found in the house, with the exception of the short tailed snake, and those with two black stripes on the back.
This proves that jinn may attack human beings. Sometimes a person will go into a secluded place, where he sees no one, but he will hear voices and sounds, or he will hear stones being thrown. When this happens, it can very possibly be jinn. Jinn can even enter the body of a human being - because they are in love with him, or for any other reason. Allaah Almighty says:

Translation:

Those who eat Riba (usury and interest) will not stand (on the Day of Resurrection) except like the standing of a person beaten by Shaytaan leading him to insanity [Al-Baqarah 2:275]

To protect ourselves from evil jinn, we should read those invocations that the Messenger of Allaah Salallaahu alayhi wasallam taught us to read, such as Ayat Al-Kursi, for when a person reads this verse during the night, he is protected, and Shaytaan does not come near him until the morning - and Allaah Almighty is the One who protects us.