Matthew 5:48

Setting and Overview
The final verse of chapter 5 is seen by some to be the conclusion to the final antithesis, and by others to be meant to refer back to and close the entire section. The evidence seems to favor the latter, and even if that were not the intention, it would seem natural to still apply the exhortation to all that has come before it. As Jesus has given the antitheses as a refutation of a legalistic application of the Mosaic law, there is still a danger that the same legalistic attitude would simply be applied to His commands here. The final verse of the chapter shows how inadequate such an approach would be, and reminds us of the direction that all of His commands point us.
 
Exposition
While the definition of perfect is pretty straightforward and almost universally understood, it is nonetheless rarely used in a way that truly conforms to the definition. When we refer to someone or something as perfect, we usually intend either a very limited aspect of perfection, or simply that they are very good. When it is used in both the Old Testament and New Testament, it often has a similar connotation. When Deuteronomy 18:13 commands perfection, it is in the context of not worshipping idols. When “perfect” lambs are commanded to be used in offerings (Exodus 12:5 and many others), it simply means free of blemishes. When it is used to describe Noah, Abraham, and David (Genesis 6:9, 17:1, II Samuel 22:21-27) it refers not to sinlessness but to being above reproach. In the New Testament, it is often used to refer to spiritual maturity (James 1:4, I Corinthians 14:20, Hebrews 5:14-6:1.) Jesus doesn’t simply command us to be perfect, however, but rather commands us to be perfect as God is perfect. Interestingly, the Old Testament never refers to God as perfect, although it does refer to aspects of His perfection (Deuteronomy 32:3-4) and it would certainly have been understood. By describing the Father as perfect here, Jesus is challenging our understanding of the standard of maturity to which we should strive. When we receive the command to be holy as God is holy (I Peter 1:15-16, quoting Leviticus 19:1-2) and in the Lukan parallel to this passage to be merciful as God is merciful (Luke 6:36, reflecting Exodus 34:5-7), the intent is not that we would strive to be like God only in those aspects. Rather, as we reflect on God’s perfection and strive to reflect His character in those areas, it should also impact our obedience to Him in other ways as well.
  
Examination and Application
There are many standards against which we could compare our obedience in the areas that Jesus has addressed in this chapter. Are we better than we used to be? Are we better than those around us? Are we meeting the standard of our mentors or those to whom we look up? Are we meeting the letter of the commands to us in Scripture? While those standards can serve some benefit, none of them should be our focus or ultimate goal, and if we stop with measuring ourselves there, then we miss Jesus’ message. Instead, our standard must be God Himself as demonstrated perfectly by Jesus Christ (Colossians 1:15, 19.) We look to Jesus as we grow in spiritual maturity (Hebrews 12:1-2), recognizing that the church and its leaders are given the responsibility to disciple us as Christians to grow to the maturity of Christ (Ephesians 4:11-13.) While this may seem overwhelming, we are given the promise that God has predestined us to exactly that standard (Romans 8:29.) This can hardly be an invitation to cease to strive for ever increasing maturity, however. Instead, we are called to follow Paul’s example of living up to the status that has already been secured for us (Philippians 3:12-16.)