When the sealing Spirit is called the Spirit _of promise_, does the expression look backward or forward? Is the apostle thinking of the past promise now fulfilled, or of some promise still to be fulfilled? The former, undoubtedly, is true. _The_ promise (the article is significant[53]) is, in the words of Christ, "the promise of the Father." On the day of Pentecost St Peter pointed to the descent of the Holy Spirit as God's seal upon the Messiahship of Jesus, fulfilling what was promised to Israel for the last days. When this miraculous effusion was repeated in the household of Cornelius, the Jewish apostle saw its immense significance. He asked, "Can any one forbid water that these should be baptized, who have received the Holy Spirit as well as we?" (Acts x. 47). This was the predicted criterion of the Messianic times. Now it was _given_, and with an abundance beyond hope,--_poured out_, in the full sense of Joel's words, _upon all flesh_.
Now, if God has done so much--for this is the implied argument of verses 13, 14--He will surely accomplish the rest. The attainment of past hope is the warrant of present hope. He who gives us His own Spirit, will give us the fulness of eternal life. The earnest implies the sum. In the witness of the Holy Spirit there is for the Christian man the power of an endless life, a spring of courage and patience that can never fail.
II. But there are very definite conditions, upon which this assurance depends. "When you heard the word of truth, the gospel of your salvation"--there is the outward condition: "when you believed"--there is the inward and subjective qualification for the affixing of the seal of God to the heart.
How characteristic is this antithesis of _hearing_ and _faith_![54] St Paul delights to ring the changes upon these terms. The gospel he carried about with him was a message from God to men, the good news about Jesus Christ. It needs, on the one hand, to be effectively uttered, proclaimed so as to be heard with the understanding; and, on the other hand, it must be trustfully received and obeyed. Then the due result follows. There is salvation,--conscious, full.
If they are to believe unto salvation, men must be made to _hear_ the word of truth. Unless the good news reaches their ears and their heart, it is no good news to them. "How shall they believe in Him of whom they have not heard? how shall they hear without a preacher?" (Rom. x. 14). The light may be true, and the eyes clear and open; but there is no vision till both meet, till the illuminating ray falls on the sensitive spot and touches the responsive nerve. How many sit in darkness, groping and wearying for the light, ready for the message if there were any to speak it to them! Great would Paul's guilt have been, if when Christ called him to preach to the heathen, he had refused to go, if he had withheld the gospel of salvation from the multitudes waiting to receive it at his lips. Great also is our fault and blame, and heavy the reproach against the Church to-day, when with means in her hand to make Christ known to almost the whole world, she leaves vast numbers of men within her reach in ignorance of His message. She is not the proprietor of the Christian truth: it is God's gospel; and she holds it as God's trustee for mankind,--that through her "the message might be fully preached, and that all the nations might hear" (2 Tim. iv. 17). She has St Paul's programme in hand still to complete, and loiters over it.
The nature of the message constitutes our duty to proclaim it. It is "the word _of truth_." If there be any doubt upon this, if our certainty of the Christian truth is shaken and we can no longer announce it with full conviction, our zeal for its propagation naturally declines. Scepticism chills and kills missionary fervour, as the breath of the frost the young growth of spring. At home and amongst our own people evangelistic agencies are supported by many who have no very decided personal faith, from secondary motives,--with a view to their social and reformatory benefits, out of philanthropic feeling and love to "the brother whom we have seen." The foreign missions of the Church, like the work of the Gentile apostle, gauge her real estimate of the gospel she believes and the Master she serves.