Our Lord’s exhortation in these verses is to be generous in our behaviour to all men. In the spiritual life beware of walking according to natural affinities. Everyone has natural affinities; some people we like and others we do not like. We must never let those likes and dislikes rule in our Christian life. "If we walk in the light as God is in the light," God will give us communion with people for whom we have no natural affinity.
The Example Our Lord gives us is not that of a good man, or even of a good Christian, but of God Himself. "Be ye therefore perfect even as your Father in heaven is perfect," show to the other man what God has shown to you; and God will give us ample opportunities in actual life to prove whether we are perfect as our Father in heaven is perfect. To be a disciple means that we deliberately identify ourselves with God’s interests in other people. "That ye love one another; as I have loved you . . .”
The expression of Christian character is not good doing, but God-likeness. If the Spirit of God has transformed you within, you will exhibit Divine characteristics in your life, not good human characteristics. God’s life in us expresses itself as God’s life, not as human life trying to be godly. The secret of a Christian is that the supernatural is made natural in him by the grace of God, and the experience of this works out in the practical details of life, not in times of communion with God. When we come in contact with things that create a buzz, we find to our amazement that we have power to keep wonderfully poised in the centre of it all.