When an individual is continually used to harass you, recognize that it is a plan of the enemy to frustrate you and cause you to lose your effectiveness.
You need to watch out in two different areas:

1. When Satan continually uses one person to harass you.
2. When he uses one person to bring strife and contention among Christians.

The Word of God tells us:

For we wrestle not against flesh  and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
(Eph. 6:12)

When an individual is continually used to harass you, recognize that it is a plan of the enemy to frustrate you and cause you to lose your effectiveness.

Just recognizing what is happening will help. Then deal with the matter in the spirit realm - in prayer and intercession.

If one person brings confusion again and again, you must bind the spirit that is influencing him. You can't grab the person by the neck and say, "I bind you in the name of Jesus!" but you can take authority over the evil spirit that is using him and command it to leave.

Christians have been wrestling against each other, instead of against the powers of darkness. That allows strife to enter in, causing confusion, contention, and every evil work.

Through strife, Satan has tried to get the members of the Church to persecute each other.

Source: Understanding Persecution by Annette Capps
Excerpt permission granted by Harrison House Publishers