How much of Christianity did Apollos know?

Les explains that Apollos was an eloquent man, mighty in the Scriptures, who came from Alexandria and was likely well educated among those who translated the Hebrew Old Testament into Greek. He was instructed in the way of the Lord, fervent in spirit, and taught diligently the things of the Lord, knowing only the baptism of John. At that time the early church had only the Old Testament; nothing of the New Testament was yet written, not even the Gospels, and Paul’s letters had not been circulated as the Bible. So the only Scriptures preached from were the Old Testament. Therefore Apollos knew none of Christianity in the Pauline sense. He knew only the Gospel of the Kingdom preached by Jesus, the twelve, and John the Baptist—repentance, baptism, and believing that Jesus was the Christ. That Gospel was still basically Jewish, connected with Temple worship, the Old Testament covenants, and the promise of the coming Messiah. Les notes that the four Gospels belong to the Old Testament, and the blood of Christ is the way to God once we get to the Pauline revelations. Apollos knew nothing of Paul’s Gospel, so Priscilla and Aquila took him aside and expounded unto him the way of God more perfectly.