These early speeches contain only a little of the full truth of the gospel. In them, for example, the significance of the death of Christ as an atonement for sin is not fully explained. Such omissions were due no doubt to two causes.
(a) Limitations Due to the Hearers.—In the first place, the peculiar needs of the hearers had to be considered. The hearers were Jews; to them the death of the Messiah was an unheard-of paradox; to them the cross was a stumblingblock. Before the inner meaning of the crucifixion could be explained, obviously the objections derived from it needed to be overcome. The first task of the missionaries was to show that Jesus, although he had been crucified, was the Messiah. That was done by an appeal to prophecy and to the plain fact of the resurrection. After conviction had thus been produced, it would be time enough to show that what was at first regarded as a stumblingblock was really the supreme act of divine grace.
(b) Limitations Due to an Early Stage of Revelation.—The omissions in the early speeches were due, however, not merely to the peculiar needs of the hearers, but also to limitations in the knowledge of the apostles. Christian truth was not all revealed at once; undoubtedly the full explanation of the cross, the full exposition of the atonement, was revealed only when the disciples could bear it. Such is the divine method, even in revelation. The disciples were brought gradually, by the gracious leading of the Holy Spirit, into ever richer knowledge of the truth.
(c) The Significance of the Cross.—Nevertheless, the meagerness of the early teaching must not be exaggerated. In the very first missionary speech of Peter, Jesus was represented as "delivered up by the determinate counsel and foreknowledge of God." Acts 2:23. What happened "by the determinate counsel ... of God" was no meaningless chance; the crucifixion was not a victory of evil over God, it must have had some beneficent purpose. Furthermore, Jesus himself had explained what that purpose was. He had spoken of giving his life a ransom for many, Mark 10:45; still more plainly, on the last solemn passover evening, he had represented his death as sacrificial. These words were certainly not forgotten in the Jerusalem church; they were called to mind in the repeated celebration of the Lord's Supper, and must have formed the subject of meditation. The Jerusalem Christians knew that Jesus' death was a death on their behalf.
(d) The Lordship of Jesus.—The lordship of Jesus, moreover, was fully recognized from the very beginning. The risen Christ had ascended into glory, and had poured forth his mighty Spirit. The believer was no mere learner of the words of a dead teacher; he was called into communion with a Lord and Saviour. Such communion meant nothing less than an entirely new life, in which sin could have no rightful place. It was a life of conflict, but also a life of hope. The Saviour would come again in like manner as he had gone. The spiritual victory, already won, would be perfected by a final victory in every realm.
(2) The Missionary Preaching of Paul.—The gospel of the early preachers was a glorious message. It was a piece of glad tidings, such as the world had never known. Yet even greater things were in store; even more wondrous mysteries were to be revealed. They were revealed especially through the instrumentality of the apostle Paul. The gospel had been preached from the beginning, but much of its deeper meaning was reserved for Paul.
(a) Truth and Error.—In the teaching of Paul, truth became plainer by being contrasted with error. The original apostles had really been trusting in the atonement of Christ for salvation; but now that trust became plainer and more explicit by being contrasted with works of the law. The original apostles had really grasped the inner significance of Jesus as the fulfillment of the Old Testament; but now that significance became still plainer by the contrast with Pharisaic legality. Now at length the death and resurrection were represented sharply and clearly as great representative acts in which the believer shares through faith. The original apostles were not overwhelmed and confused by the new revelation; they recognized the grace of God. Their perfect agreement with Paul exhibited the unity of the apostolic gospel.
Scarcely anything would be more interesting than a full collection of the missionary speeches of Paul. Such a collection, however, has not been preserved. The writings that we possess from the hand of Paul are not missionary addresses, but letters written to those who were already Christians. We should not, however, complain of the providence of God. God has not thought good to give us everything, but what he has given us is enough.
(b) Information Provided by The Acts.—The book of The Acts, in the first place, affords valuable information. The author was interested, indeed, chiefly in beginnings. The examples of Paul's missionary preaching which Luke has preserved, are perhaps preliminary to evangelism, rather than evangelism itself. The speech at Pisidian Antioch shows how Paul proved the Messiahship of Jesus. In winning the Jews, that proof was the first step. The Pauline gospel indeed appears, but it appears only at the very end of the speech. The speech at Athens is still more clearly of preliminary character. Monotheism needed to be established before the gospel of Christ could be understood. Despite their necessary limitations however, these speeches are instructive. They show, in the first place, that Paul adapted his preaching to the needs of his hearers. He did not preach the same sermon mechanically to all. He sought really to win men over, he began with what his hearers could understand. They show, in the second place, that all preliminary matters were kept strictly subordinate. These matters were not made an end in themselves, as is often the case in the modern Church, but were merely a means to an end. No matter where he began, Paul always proceeded quickly to the center of the gospel. Both at Pisidian Antioch and at Athens, he hastened on to the resurrection.