Few problems are more obscure than the question of the growth of baptism in the Church of this first period. This is due to the fact that the editor of Acts was convinced that baptism was a primitive Christian custom even in Jerusalem, though unlike Matthew he does not attribute it to Jesus. Nevertheless, it is possible to see indications that his sources did not confirm his opinion. An excellent case can be made for the view that the source used in Acts i. and ii. originally regarded the gift of the Spirit at Pentecost as the fulfilment of the promise attributed to Jesus that his disciples, unlike those of John, should be baptized in the Holy Spirit not in water. The exhortation of Peter in Acts ii. that his hearers should repent and be baptized is so inconsistent with this promise that it seems due to the redactor. Similarly, too, the baptism of Cornelius seems to contradict the context of Peter's own explanation in Acts xi., and may well be redactorial. On the other hand, the later chapters agree with these redactorial additions in regarding baptism as the source of the gift of the Spirit, and there can here be no question of editorial additions, for the references to baptism are clearly part of the fabric of the narrative. The most illuminating evidence, however, is afforded by the chapters describing Philip's work: in these baptism in the name of the Lord Jesus is represented as the custom of Philip, but it does not confer the gift of the Spirit. This may be the best clue to the historical development of the rite. The Seven, including Philip, were probably the first to convert Gentiles, and inasmuch as the complete breach with Judaism had not yet come, must have regarded their converts as proselytes, and treated them accordingly. Baptism was part of the usual treatment of a proselyte, and the formula "in the name of the Lord Jesus" would merely distinguish these proselytes from others.

A little later the practice would certainly be interpreted by Greeks, or Graeco-Orientals, in the light of the cults which they knew; baptism would become the magical or, at least, sacramental means of salvation, and the Name of Jesus its necessary formula. The development is exactly similar to that passed through by the word "Lord,"—though its origin was Jewish its interpretation was Greek.[[7]]

The expectation of immortality conferred by Baptism and membership in the Church of the Lord Jesus varied in form. The Greek eschatology was different from the Jewish, and looked for an immortality for each individual immediately after death. It was, moreover, an immortality of the soul, not of the body. Probably there were many variations of thought on the subject. Some of the most highly educated Greeks may have understood the arguments for and against immaterial Reality, and accepted or rejected them. Roughly speaking, Platonists accepted, Stoics and Epicureans rejected; and it was at least possible for Platonists, if they identified Mind with immaterial Reality, to believe in the immortality of the human mind. But did such Platonists actually exist before Plotinus, or possibly Ammonius Saccus? The fragmentary evidence which exists seems to show that philosophic Greeks were interested in other problems—mainly epistemological and psychological. The belief in the immortality of the soul was preserved by the tradition of the Mysteries,[[8]] not by the Academy. Stoics and Epicureans, far more important for the first century than Academics, were materialists; but that does not mean that they did not believe in the existence of a human soul or spirit. Spirit was for them merely the most attenuated form of matter. The spirit of man might be dissipated after death, as the grosser material composing his body would be, or it might survive and retain consciousness and memory until the cycle came round when all things, including human careers, would be repeated.

But the first Greek Christians were scarcely influenced by an intelligent comprehension of Stoic metaphysics, and attempts made to trace their direct influence in Paul or elsewhere only show that their vocabulary was more widely used than their problems were understood—a phenomenon not peculiar to the first century. All that can be said with any confidence is that the expectation of blessed immortality—not for all but for the chosen few—fostered by the mysteries was probably most often conceived as the survival of the soul after death, and the soul in turn was conceived as "Spirit," a highly attenuated material existence, which was found until death in the body, and was then released from it.

In some such way the Greeks in Corinth who were converted to Christianity expected immortality. So they did also in the other cults offering salvation. The points of difference in Christianity are in the kind of life which was demanded from initiates, and in the final consummation expected.

1 Corinthians shows clearly that some Hellenic Christians held that having secured immortality they were free to do as they liked with their bodies. Paul insisted on the observance of that morality which was central in Judaism. He had rendered his task difficult by his rejection of the Law, but he won his fight, and the permanent association of Jewish morality with the Christian Church and its Hellenic Christology and sacraments was the result.

In the same way Paul contended successfully for the Jewish doctrine of a resurrection, though with some modifications. This was not the same thing as the Greek belief in personal immortality. The Sadducees, indeed, may have Hellenised on this subject, as did some of the Alexandrian Jews, represented by the Wisdom of Solomon. But the bulk of the people followed the Pharisees and looked for a resurrection of the body, at the end of the age.

Paul and the other missionaries continued to teach this Jewish doctrine, but were not at once able to convince their Greek hearers that immortality must necessarily be reached through a resurrection of the body. Presumably the Greeks felt that immortality was sufficient, and a future reunion between an immortal soul and a resuscitated body was as undesirable as improbable. Paul in 1 Corinthians insists on the Jewish doctrine, but he makes the concession to the Greeks that the resurrection will not be of flesh and blood but of a "spiritual" body, that is to say, a body consisting of the most attenuated form of matter. It will be the same body, but it will be changed.

This modified form of Jewish thought was supported by an appeal to the case of Jesus, who had already risen from the dead. The appeal was really far more effective than the rest of Paul's argument, which was not calculated to convince the doubtful, and it has the especial importance for the historian that it proves that Paul did not think the risen Jesus had a body of flesh and blood, and believed that in this he was in agreement with all the early witnesses.

Nevertheless, the belief of the Church soon affirmed what remained its unchanged faith until the nineteenth century—the resurrection of the flesh, both of the Lord in the past, and of the Christian in the future. This was the triumph of Jewish thought, and is an exception to the general rule that Christianity became steadily more Hellenic.