In part two we are to separate ourselves from Christians who are unruly, meaning they are morally disorderly. (See 2 Thess.3:5-7; Matt.18:15-17)
In part three we are to separate ourselves from Christians who do not follow the Word of God given to them. (See 2 Thess.3:14-15; Rom.16:17-18)
In part four we are to separate ourselves from Christians who walk in a lifestyle of sin. (See 1 Cor.5:9-12).
In part five we are to separate ourselves from those who walk in the lifestyle of sins (See 1 Tim.6:3-21).
In part six we are to separate ourselves from those who are lost, unsaved, children of wrath, children of the enemy or any other name which the Bible identifies them. (See Jam.4:4)
In part seven we are to separate ourselves from false teachers.(See 2 Jn.1:9-11)
Now here in part eight we see that our Lord says that we are in the world but we are not of the world. We need to separate ourselves from the worldly system and the evil of it. In salvation we have been freed from the penalty of sin and from the power of sin. However, the power of sin and the presence of sin that will affect us defends on how much of the world we allow within our daily lives and activities. There is an old saying which goes like this: "You cannot play with fire very long without getting burned."
John 17:14-17 ESV I have given them your word, and the world has hated them because they are not of the world, just as I am not of the world. (15) I do not ask that you take them out of the world, but that you keep them from the evil one. (16) They are not of the world, just as I am not of the world. (17) Sanctify them in the truth; your word is truth.