48 Be perfect, therefore, as your heavenly Father is perfect.- Matthew 5:48
But let's look at the whole context of the verse.
43 “You have heard that it was said, ‘Love your neighbor[i] and hate your enemy.’ 44 But I tell you, love your enemies and pray for those who persecute you, 45 that you may be children of your Father in heaven. He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. 46 If you love those who love you, what reward will you get? Are not even the tax collectors doing that? 47 And if you greet only your own people, what are you doing more than others? Do not even pagans do that? 48 Be perfect, therefore, as your heavenly Father is perfect.- Matthew 5:53-48
What does Jesus mean about being "perfect". If none are good and sinless but God, then what does it mean to be perfect considering that we will never be God? The context with the Greek tells us what the answer is. The context is Jesus drawing a distinction of behavior showing how inconsistent it is to love your neighbor but neglect loving your enemies. He points out that if you don't love your enemies you are doing no more than what people you look down as being less moral than you do. If you want to be perfect you have to love and greet not just your friends but people who hate you and don't care for you. It isn't about being sinless, it is about being a complete person under God's definition.
A short little word study bears this out. The word here translated "perfect" is "tevleioß" it is defined as:
- brought to its end, finished
- wanting nothing necessary to completeness
- that which is perfect
- consummate human integrity and virtue
- of men
- full grown, adult, of full age, mature (source)
Nothing to necessarily be referring to sin.
Is this word used in any other places? Yes. A related word "teleiovw" is also translated "perfect" in the following passage
7 During the days of Jesus’ life on earth, he offered up prayers and petitions with fervent cries and tears to the one who could save him from death, and he was heard because of his reverent submission. 8 Son though he was, he learned obedience from what he suffered 9 and, once made perfect, he became the source of eternal salvation for all who obey him 10 and was designated by God to be high priest in the order of Melchizedek.- Hebrews 5:7-10
Is the author of Hebrews implying that Jesus had to be made perfect by purging his sins? No. Given all the passages we have about Jesus' sinlessness, we can't conclude that the passage is referring to sins. "Perfect" in this case is like in Matthew 5:48. Jesus was made complete in his role as the source for our salvation by the suffering he endured for us!
There is another passage, I just love, that uses a similar word. Jesus last words on the cross before He died saving all those who believe in Him.
30 When Jesus therefore had received the vinegar, he said , It is finished : and he bowed his head, and gave up the ghost. - John 19:30
Here "It is finished." is translated from "Teleo".
- to bring to a close, to finish, to end
- passed, finished
- to perform, execute, complete, fulfil, (so that the thing done corresponds to what has been said, the order, command etc.)
- with special reference to the subject matter, to carry out the contents of a command
- with reference also to the form, to do just as commanded, and generally involving the notion of time, to perform the last act which completes a process, to accomplish, fulfil
- to pay
- of tribute
It was truly finished on the cross. All my sins paid for. The term is so amazing because it is also the same idea of saying "it's perfect" or "It doesn't get any better than this". It's like when a painter or an artist finishes a piece of art and is fully satisfied with what is produced. It was equivalent to saying "Voilà!!!" or "Check mate." And all I can say is "Amen."