Paul uses verses 1-16 to show how the church is to be unified and be thankful for the people that have touched our life and made a difference in it.
He then gives instruction for us to be careful of people that will come into our lives. They will try to cause division and put obstacles in our way that do not agree with what we have been taught. They try to do this with flattery and vain words.
When we men are full of the Spirit, we will be able to recognize that spirit and make them feel uncomfortable and they will not stay around.
Randal Sheppard