It means that does that are not born of God can be touched by Satan, by evil spirits.
The book of first John chapter 5 verse 18 says we know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not. Evils or the evil spirits pr Satan and his cohorts cannot touch does that are born of God what does that mean? It means that those that are born of God can be touched by Satan by evil spirits the bible is classifying that does that cannot be touched by the evil one or Satan are those begotten of God that it themselves, he that is begotten of God keepeth himself meaning he watch over himself, his actions, emotions, character, his dealing with people, and his belief.
He watch himself, he's careful about himself, he his not a reckless person and that person begotten from God cannot be touched by evil spirits,no evil spirit can touch or take hold on you but it means that people who are not like those begotten of God or the children of God can be touched by evil. So if you have seen a movie or whatever it may be that there are people being touched by evil spirits. Sometimes evil spirits play on them, it dwell in there person sometimes.
Those who serve and believe in God cannot be touched in a rightful manner, they cannot be touched by evil spirits. Those who do not believe and serve him can easily be influenced and touched by evil, the devil can even dwell in their person that what they call possessed.
So you have to believed and serve the lord so as to avoid been touched by evil spirits and the devil.