Encourager and Apostle of the Church
Joses is a unique individual. This Levite is the first Christian outside of the twelve apostles to be named in the book of Acts (4:36).  He was so well-known and well-loved by the twelve that they gave him the nickname “Barnabas,” which means “son of exhortation.” This nickname stuck, and it is the only name by which he is mentioned throughout the rest of the Bible.
Barnabas sold some land to make sure that the poor Christians in Jerusalem had enough to eat, and he placed it in the care of the apostles. Other people did similar things, but Barnabas is the one who is singled out in the history of the early church, because he plays a much bigger role later on. But from this, we can see that Barnabas truly cared for his brethren in Christ. He wasn’t concerned about building wealth for himself, nor was he worried about owning a lot of land. He was more interested in “how can I help others.” He was a helper and an encourager. This made him stand out in the eyes of the apostles.
Barnabas next appears some years later, and still showing these same qualities. Saul of Tarsus, the former Christian-killer, had seen the light and obeyed Christ, but he had a very difficult time convincing the church of that. In fact, the Christians in Jerusalem wanted nothing to do with him—they thought he was lying, attempting to trick them so that he could drag them all into prison (Acts 9:26). But while the whole church at Jerusalem rejected Saul, Barnabas stood up for him. Barnabas met with Saul and heard his side of the story. Then he arranged a meeting with the apostles, where he—Barnabas—told them that Saul had seen Jesus in the road, and that the Lord had spoken to him, and that he had preached boldly in Damascus. Barnabas didn’t just arrange this meeting, he put his entire reputation on the line by standing up for Saul of Tarsus. And it was because of the support of Barnabas that Saul became a welcome member there (Acts 9:27-28).
Some time soon thereafter, Saul’s life was threatened, so the brethren sent him back to his home of Tarsus. But then came momentous news, that the Gentiles were now being accepted by God into His church! Cornelius and his family had been converted, and then several Christians in Antioch began converting large numbers of Gentiles. It is here that Barnabas again appears.
The church in Jerusalem heard this wonderful news and sent Barnabas to Antioch. The Greek word used in Acts 11:22 for “sent forth” is the verb form of “apostle.” Barnabas was, at this point, an apostle of the church in Jerusalem, sent to see what was happening in Antioch. When he arrived, he was overjoyed and served as an encourager to them, bringing many people to the Lord. But Barnabas had other plans as well. He remembered a young man named Saul who was a bold preacher, and who had to be sent back home to Tarsus to keep him safe. Barnabas went to Tarsus and found his friend. Saul had not lost his zeal for the Lord and they both returned to Antioch, where they worshiped with the church for a whole year (Acts 11:23-26).
Around that time, a prophet came to Antioch, telling them about a great famine that was going to come upon Judea. The Christians in Antioch all pitched in to aid their brethren, and when it came time to choose two men that they trusted enough to send to Jerusalem with all that money, it was Barnabas and Saul. The word “sent” in Acts 11:30 is the verb form of “apostle.” Barnabas went from being an apostle of the church in Jerusalem—sent to Antioch—to being an apostle of the church in Antioch—sent to Jerusalem. And when their mission was completed, they went back to Antioch (Acts 12:25-13:1). Barnabas was a man who made sure he saw his mission through to the end, and didn’t shirk in the face of difficulty.
-Bradley S. Cobb
 The church did not come into existence until the Day of Pentecost in Acts 2. There were disciples of Jesus mentioned by name in Acts 1, but at that point, there was no church to be a part of.
 A very few ancient Greek manuscripts have “Joses Barnabas” instead of “Joseph Barsabas” in Acts 1:23, and from that, some have suggested that Barnabas was one of the two men considered to take Judas’ place as an apostle. The evidence is against this. First, the significant majority of manuscripts do not say “Joses Barnabas.” Second, the man in Acts 1:23 is called “Justus,” and that name is never used to describe the man we know as Barnabas. Third, when Barnabas appears on the scene in Acts 4:36, Luke introduces him as someone that has not yet appeared in the book (giving name, surname, birthplace, Jewish ancestry, etc…). These considerations eliminate the idea that Barnabas was the one who wasn’t chosen to replace Judas Iscariot.
 KJV says “son of consolation,” Acts 4:36.
 Estimates range from just a few months to nearly 10 years, depending on which commentary you read.