"Now a Jew named Apollos, a native of Alexandria, came to Ephesus, he was an eloquent man, competent in the Scriptures." (Acts 18:24, ESV)
Thus we have the first mention of Apollos in the New Testament. As many times as Apollos was mentioned in the New Testament very little is know about this great man of God. The information that we have of Apollos comes from the Acts, I Corinthians, and an epistle.
Our first glimpse of Apollos is seen when he travels to the City of Ephesus. The Scriptures tell us first, that he was from Alexandria, Egypt. Alexandria was in the Nile Delta region of Egypt and had been established by Alexander the Great. Alexandria was famous for its libraries and was a center for Greek learning. It was in Alexandria that the Septuagint translation of the Old Testament was made. Alexandria had a very large Jewish population. Alexandria was a world-wide commerce center. A great school of learning developed in Alexandria.
Secondly, we see that Apollos was very knowledgeable of the ministry of Jesus Christ. We do not know if Apollos was taught this information in Alexandria or elsewhere. Luke tells us however, that Apollos knowledge or information was not complete. The Scripture tells us that Apollos was only aware of the baptism which had been instituted by John the Baptist. The baptism in the name of Jesus which had been preached by Peter on the Day of Pentecost was unknown to Apollos. What is important for us to note is that Apollos combined great biblical learning and accurate knowledge of the story of Jesus with such spiritual enthusiasm that he proved to be specially gifted in showing from the Old Testament that Jesus was the long awaited and promised Messiah.
Aquila and Priscilla heard Apollos one day preaching the Old Testament Scriptures in the Synagogue in Ephesus. They were greatly impressed with both his understanding and his passion. Apollos did not seem to know the full extent of the gospel that he was so enthusiastically preaching and so they invited him to their home in Ephesus. There they taught him what he did not know and filled in the gaps that existed in his learning.
Apollos seems to have visited the Church at Corinth in between Paul's second visit to the church and the writing of what we know as I Corinthians. Apollos then returned to Ephesus where he joined the Apostle Paul. They talked much we are sure of the situation at Corinth. Paul even urged Apollos to return to Corinth and help straighten things out but Apollos declined, having other plans.
Paul and Apollos maintained their love for one another. When Paul wrote Titus when Titus was stationed on the Island of Crete, Paul instructed Titus to assist Zenas (lawyer) and Apollos in every way possible so that neither of them lacked anything.
We don't know why Apollos and Zenas were traveling to Crete. Later in history, Jerome records for posterity that the reason Apollos left the Corinthian Church was that he was so frustrated with the divisions between the believers. Jerome also states that after Paul's extensive dealing with the church that Apollos eventually returned to the Corinthian Church and became its pastor. We do not know this for sure nor do we have proof of this.
Martin Luther along with some modern day theologians believe that the Epistle to the Hebrews was written, not by Paul, Timothy, Luke, or Barnabas, but by Apollos. We have absolutely no evidence to support this hypothesis. However, it is interesting to think about! :)