5:20-21 So then we are acting as ambassadors on Christ's behalf, for God is sending you his invitation through us. We beseech you on behalf of Christ, be reconciled to God. He made him who had no acquaintance with sin to be sin for us, that through him we might become the righteousness of God. Because we are trying to help him to win men, we urge you not to have received the offer of the grace of God all to no purpose. (For scripture says, "At an accepted time I heard you, and in the day of salvation I helped you." Lo! Now is the accepted time. Lo! Now is the day of salvation).
The office that Paul claims as his one glory and his one task is that of ambassador for Christ. The Greek he uses (presbeutes, compare Greek #4246 ) is a great word. It had two uses corresponding with the Latin word of which it is a translation (legatus).
(i) Roman provinces were divided into two types. One was under the direct control of the senate, the other under the direct control of the Emperor. The distinction was made on this basis--provinces which were peaceful and had no troops in them were senatorial provinces; provinces which were turbulent and had troops stationed in them were imperial provinces. In the imperial provinces, the man who administered the province on behalf of the Emperor, was the legatus presbeutai. So then, the word in the first place paints a picture of a man who has a direct commission from the Emperor; and Paul regarded himself as commissioned by Jesus Christ for the work of the Church.
(ii) But presbeutes (compare Greek #4246 ) and legatus have an even more interesting meaning. When the Roman senate decided that a country should become a province they sent to it ten legati or presbeutai, that is, envoys, of their own number, who, along with the victorious general, arranged the terms of peace with the vanquished people, determined the boundaries of the new province, drew up a constitution for its new administration, and then returned to submit what they had done for ratification by the senate. They were the men responsible for bringing others into the family of the Roman Empire. So Paul thinks of himself as the man who brings to others the terms of God, whereby they can become citizens of his empire and members of his family.
There is no more responsible position than that of ambassador.
(i) An ambassador of Britain is a Briton in a foreign land. His life is spent among people who usually speak a different language, who have a different tradition and who follow a different way of life. The Christian is always like that. He lives in the world; he takes part in all the life and work of the world; but he is a citizen of heaven. To that extent he is a stranger. The man who is not willing to be different cannot be a Christian at all.
(ii) An ambassador speaks for his own country. When a British ambassador speaks, his voice is the voice of Britain. There are times when the Christian has to speak for Christ. In the decisions and the counsels of the world his must be the voice which brings the message of Christ to the human situation.
(iii) The honour of a country is in its ambassador's hands. His country is judged by him. His words are listened to, his deeds are watched and people say, "That is the way such-and-such a country speaks and acts." Lightfoot, the great Bishop of Durham, said in an ordination address, "The ambassador, while acting, acts not only as an agent, but as a representative of his sovereign.... The ambassador's duty is not only to deliver a definite message, to carry out a definite policy; but he is obliged to watch opportunities, to study characters, to cast about for expedients, so that he may place it before his hearers in its most attractive form." It is the great responsibility of the ambassador to commend his country to the men amongst whom he is set.
Here is the Christian's proud privilege and almost terrifying responsibility. The honour of Christ and of the Church are in his hands. By his every word and action he can make men think more-or-less of his Church and of his Master.
We have to note Paul's message. "Be reconciled to God." The New Testament never speaks of God being reconciled to men, but always of men being reconciled to God. There is no question of pacifying an angry God. The whole process of salvation takes its beginning from him. It was because God so loved the world that he sent his son. It is not that God is estranged from man but that man is estranged from him. God's message, the message which Paul brought, is an appeal from a loving Father to wandering and estranged children to come home where love is waiting for them.
Paul beseeches them not to accept the offer of the grace of God all to no purpose. There is such a thing--and it is eternity's tragedy--as the frustration of grace. Let us think of the matter in human terms. Suppose that a father sacrifices and toils to give his son every chance, surrounds him with love, plans for his future with care, and does everything humanly possible to equip him for life. And suppose the son feels no debt of gratitude, never feels the obligation to repay by being worthy of all this; and suppose he fails, not because he has not the ability, but because he will not try, because he forgets the love that gave him so much. That is what breaks a father's heart. When God gives men all his grace and they take their own foolish way and frustrate that grace which might have recreated them, once again Christ is crucified and the heart of God is broken.
-Barclay's Daily Study Bible (NT)