Therefore you will be perfect, as your heavenly Father is perfect.
This verse begins with one of those pesky therefores. What is that word there for?
What precedes this verse is the Beatitudes as well as instructions for living. Jesus has been saying things that are still challenging and still cause wrangling in the church today. Statements like cut out your right eye if it causes you to stumble (which is most often taken to mean that we should take drastic measures to address the sins in our lives) cause many, myself included, to squirm in discomfort. Jesus advocates drastic measures to deal with a drastic problem, viz. sin.
The result, however, of these drastic measures; the result of dealing with sin decisively is that we will be perfect. This is not perfect in the way that most people understand it, but rather that we will be mature, finished, complete, lacking nothing. It is not to say that we will be without defect or sin. God has only One Son without sin. But it is to say that we will be mature, handling things in a way that makes our Father smile. It is to say that we will be complete. There are too many people wandering around, trying to find that one thing that will fulfill them. God is promising that I will have that piece; that I will not be lacking anything.
The quid pro quo is that I must treat sin as utterly sinful; I must take drastic measures to address the wrongs in my life, because God took drastic measures to deal with my sin. He demands nothing from me that He has not already done Himself.
As I examine myself this morning, I note that there are areas wherein I have not taken the drastic steps necessary to cut that sin out of my life. It is well past time that I did. The result is that I will be mature; complete; finished. Dear God, how I want to be finished with the sins that beset me.