In Matthew 5:48, the word “perfect” is teleios, and the Vines Expository Dictionary of New Testament Words defines it as “signifies having reached its end (telos), finished, complete, perfect.” For its use in this verse: “complete, conveying the idea of goodness without necessary reference to maturity…”
To get a fuller sense of Matt. 5:48, we must read the entire Sermon on the Mount (chapters 5-7), of which this verse is a part. But the gist of the matter is that the perfection God desires of us is to have a heart inclined toward God in surrender and humility, and toward people as a sympathetic helper, as one who shares in their frail humanity (that is, does not think himself as superior to others).
“Love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you” (5:44) are all expressions of this inward state of humility before God and man. It is not a natural state; our natural bent is to put ourselves first. It’s the state of a person who has allowed God to fashion him according to His will. If you are in the kingdom of God (that is, if Jesus is the king of your life and is having His way), then the process of sanctification will lean in this direction.
In all the helpful actions in this Sermon, the victim sees in his enemies, haters, and persecutors people who do such things because they do not know God and are acting out of personal weakness. As Jesus said from the cross, “Father, forgive them, for they know not what they do” (Luke 23:34). There is no retaliation because the victim himself knows this frailty and has found God sustaining him. The victim doesn’t take it personally, but exhibits something of the grace that God has for sinners. God is love (with many other attributes — don’t make Him a one-dimensional God!), and His desired end is that we be those who act out of love, too.
Showing love to others who don’t deserve it is what perfection looks like to God. That is the fruit of love that comes from the Spirit. We are talking about the kingdom of God here. These traits come from a God-made character. We cannot produce this fruit by our religious efforts; only God can do this.
