1. Whether Apollos immersed these 12 men or not is not absolutely clear. It is probable that he did. However, what is absolutely clear is that the Holy Ghost in inspiring the Scripture saw fit to place these two incidents in immediate juxtaposition. The chapter division, it is admitted by all, was not made by Luke, but by a later man. In reading these 12 verses without a break there are certain resemblances and parallels which ought not to be ignored. That we are intended to consider each incident in light of the other is certain if we would study Scripture in its context.
2. Apollos, "born in Alexandria" (18:24) which was in Egypt would no doubt have traveled through Judea on his journey to Ephesus. Sailing vessels were small and visited many ports as they sailed round the coast of the Mediterranean, not venturing directly across that body of water.
3. Being himself a Jew (18:24) it is unthinkable that Apollos would have not taken the opportunity to visit the land of his fathers on such a trip. We may rightly suppose that he may have remained in Judea for one or more of the religious festivals commanded by the Lord in the Old Testament.
4. These 12 men at Ephesus had an imperfect knowledge of the "way of God" in some sense similar to the imperfect understanding which Apollos had. (18:25, 26)
5. It is certainly possible that these 12 men had never heard John preach for they were separated from John by many hundreds of miles and perhaps 25 years.
6. These 12 men cannot have heard John preach for they had not even heard of the Holy Ghost (19:2), while John's preaching included the work of the Holy Spirit (John 1:33). These 12 were ignorant even of the full content of John's preaching.
7. That the Holy Ghost intends that we understand these men to be regenerate seems clear for they are called "disciples" a term reserved for "Christians" or true believers in the Acts and epistles Acts 11:26; 26:28; 1 Pet. 4:16). In the gospels the term "disciples" is used in a broader sense of all who were partakers of the Lord's personal teaching ministry, even those who were unsaved and who later fell away. However, after the ascension of the Lord, no person than those truly regenerated by the Holy Spirit can rightly be said to be personally taught by the Master, hence the use of the word is from that time and circumstance limited to truly saved persons.
8. We cannot suppose that these were unbelievers for Paul acknowledges that they were believers when he inquired of their receiving the Spirit "since" or "upon" their believing (19:2). If Paul accounted them believers we must understand them to be regenerated persons.
9. That these men were "rebaptized" - rather baptized "anew" by Paul seems clear since the grammar indicates it though a few have suggested that the "they" in verse 5 refers to John's hearers and the "them" and the "they" in verse 6 refers to the 12 men in Ephesus. The "they" in verse 5 MUST refer to the 12 men at Ephesus for they were "baptized in the name of the Lord Jesus" - a thing which John never did! John baptized with his own authority directly given him by God (John 1:33) NOT with Christ's authority. This is obvious when it is remembered that John was actively baptizing before he was made to know who the Messiah actually was (see John chapter 1 and elsewhere).
10. That these men were baptized anew by Paul is clear from the fact that the subject under question is the matter of baptism. Paul uses the word "baptized" in his questioning them and remarked about John's work using the word "baptized" and "baptism" thus including the word 3 times in his speech to them. The question is not "were hands laid on you?" but "unto what then were ye baptized?" (19:3). This question was raised because Paul did not observe any of the outward sign gifts of the Sprit unique to that time period when such signs were given as a confirmation of the work of God, the Scriptures being yet incomplete. Paul perceived that these Christians were lacking something in their understanding and lives, though he did not immediately know what it was that was missing. He did not question whether or not they were believers: what he determined was that they did not have the Holy Spirit for the temporary signs and evidences which at that particular time was necessary and this was missing. (I am told that EW Bullinger in "The Giver and His Gifts" indicates that when the definite article is missing before the terms the reference is to the gifts rather than the person of the Holy Spirit. The meaning here is that Paul questioned them due to the absence of the gifts.) That this whole incident is unique to the time period in which it occurred must be granted. Since the temporary sign gifts are no longer present in the earth today, and since the scripture has been completed it is not possible that this situation develop in our day.
11. Paul did not baptize anew these 12 men because there was anything wrong with John's baptism. Apollos had John's baptism (18:25) and he was not "rebaptized". John's baptism was all that Christ and His apostles had and they were not required to be baptized anew. Sound Baptists today continue John's baptism which is administered "for repentance" i.e. because of repentance, looking toward the One John identified as "the Lamb of God" (John 1:36). (Baptism "for" repentance does not mean in order to bring about repentance! A wise parent will sometimes spank his child "for" disobedience - not in order to bring about disobedience, but because of disobedience!)
12. Paul did not baptize anew these 12 men because they were not immersed in the name of the Trinity. Baptism in the name of the Trinity is not necessary to Scriptural baptism. In fact, the idea of ritualistic words being required is a Romish one and not a Scriptural one at all! To do something "in the name of" means "with the authority of" so that whether baptism is administered "in the authority of" Christ or "in the authority of the Father, Son and Holy Spirit" it is the same. Baptism does not depend on the words uttered, but in the authority under which the administrator acts. In fact, it is here stated (19:5) that these 12 men were immersed anew "in the name of the Lord Jesus" - no mention being made of the other two persons in the Godhood.
13. These 12 men were not said to have John's baptism. Apollos was said to have John's baptism (18:25). These 12 were immersed by someone (Apollos?) "Unto John's baptism" (19:3). They were looking to John as the authority for their baptism. While John, in fulfilling his inistry had authority to baptize, he had no authority to delegate that authority to others. Nowhere do we read that John's disciples ever rightly administered baptism. Repentant sinners went to John for Baptism.