Therefore you shall be perfect, just as your Father in heaven is perfect. (Matthew 5:48)
Ask your Heavenly Father to teach you to love. Remember Galatians 5:22. Dare to believe that He will perfect what concerneth you.
“You therefore shall be perfect, as your heavenly Father is perfect.”
The first thing to note here is that ‘you’ is both plural (in contrast with much of what has gone before) and emphatic. It means ‘you band of disciples’ (you new congregation of Israel), in contrast with all others. This idea of the completeness and ‘perfection’ of the whole body particularly comes out in Ephesians 4:12-13. Those separated to God (His ‘saints’ or ‘holy ones’), who are being taught by those appointed by God, are to be ‘perfected’ for His service. And that will go on until ‘we all attain to the unity of the faith and the knowledge of the Son of God, to a ‘perfect’ man, to the measure of the stature of the fullness of Christ’ This is the aim set before God’s people as a whole. By this the Kingly Rule of Heaven will be manifested and they will be the light of the world. So while it applies to each, it also applies to all, and when one comes short he mars the whole body. In view of this it can therefore only indicate potential perfection rather than present perfection, the hope of what is to be striven for and finally achieved.
Here in the context of Matthew we may see this command statement as either closing off these few verses (Matthew 5:43-48) or as closing off this whole section (Matthew 5:17-48). If the former it has in mind the universal and all-embracing love of God described in Matthew 5:43-48. Their ‘perfection’ or ‘completeness’ will be revealed by their being ‘all embracing’ in their love like God is. Those who fail to love all will not be ‘perfect’ as their heavenly Father is, for He does love all, and they will thereby mar the whole body. Alternately it may be emphasizing the need to fulfil all that is contained in the Law and the Prophets concerning God’s Instruction, as in Matthew 5:17. In this case it has in mind the need to observe every last detail of God’s Instruction (Matthew 5:19), thus being ‘like God Himself’ by seeking to achieve the total fulfilment of His revealed will. That is why those who break one of the least of the commandments and teach men so will be called ‘least’ in the Kingly Rule of Heaven (Matthew 5:19). They are a blot on the whole. For, as we will see below, being ‘perfect’ is often linked with conforming to the whole will of God.
We may also see ‘you shall be’ as indicating firstly what their aim must be, they are to be ‘perfect’ in their loving and in their living as God is, and secondly as indicating what will in the end be the result of their being His disciples and totally committed to His will. They will become ‘perfect’ in the fullest possible sense, for they will one day be like Christ, and will see Him as He is, which is why they are now to seek to purify themselves even as He is pure (1 John 3:2-3).