Apart from a doubtful reference in Tit 3:13, we derive our knowledge of Apollos from 1 Cor. and Ac 18:24-28. In Acts he is described as an Alexandrian Jew, an eloquent man, with an effective knowledge of the OT. He came to Ephesus before St. Paul sojourned there, and, having been instructed in the way of the Lord, he zealously proclaimed his views in the synagogue, where Priscilla and Aquila heard him. What exactly his views were, it is not easy to decide. Ac 18:25 suggests that he was a Christian in some sense, that he knew the story of Jesus, believed in Him as Messiah, but did not know of the coming of the Holy Ghost. The disciples mentioned in Ac 19:1 ff., who are clearly in a parallel position, do not seem to know even so much as this; and 'instructed in the way of the Lord' need not mean Christianity, while even the phrase 'the things concerning Jesus' may refer simply to the Messianic prophecies (cf. Lu 24:27, and see art. 'Apollos' by J. H. A. Hart in JThS, Oct. 1905). In Ephesus, Apollos may have preached only John's baptism of repentance. But Priscilla and Aquila made him a full Christian.
Later on Apollos worked in Corinth, with great success. His eloquence and Philonic culture won him a name for wisdom, and made his preaching attractive, so that many declared themselves his special followers (1Co 1:12). Apollos' teaching in Corinth may have been marked by allegorical interpretation, insistence on Divine knowledge, and on the need of living according to nature (see St. Paul's sarcastic reference to 'nature' in 1Co 11:14). But the party-strife at Corinth was not of his intending. Apollos and Paul were agreed in their gospel (1Co 3:8)