"Joseph, a Levite, born in Cyprus, whom the apostles called Barnabas (son of encouragement), sold a field he owned, brought the money, and turned it over to the apostles." (Acts 4:36). This is the first mention we have of Barnabas.
His new name fits what we know of his actions. When Saint Paul came to Jerusalem after his conversion, most of the Christians there wanted nothing to do with him. They had known him as a persecutor and an enemy of the Church. Barnabas, on the other hand, was willing to give him a second chance. He looked him up, spoke with him and brought him to see the other Christians, vouching for him. Later, Paul and Barnabas went on a missionary journey together to Antioch, taking Mark, who was a cousin of Barnabas, with them.
“At Iconium Paul and Barnabas went as usual into the Jewish synagogue. There they spoke so effectively that a great number of Jews and Greeks believed. But the Jews who refused to believe stirred up the other Gentiles and poisoned their minds against the brothers. So Paul and Barnabas spent considerable time there, speaking boldly for the Lord, who confirmed the message of his grace by enabling them to perform signs and wonders.”(Acts 14:1-3)
Part way, Mark turned back and went home. When Paul and Barnabas were about to set out on another such journey, Barnabas proposed to take Mark along, and Paul was against it, saying that Mark had shown himself to be undependable. Barnabas wanted to give Mark a second chance, and so he and Mark went off on one journey, while Paul took Silas and went on another. Apparently Mark responded well to the trust given him by the "son of encouragement," since we find that Paul, who clearly had healed his rift with Barnabus, later speaks of him as a valuable assistant (2 Timothy 4:11; see also Colossians 4:10).
Tradition has Barnabas preaching in Alexandria and Rome and, later, the founder of the Cypriote Church and has him stoned to death atSalamis about the year 61. The apochryphal Epistle of Barnabas was long attributed to him, but modern scholarship now attributes it to a Christian in Alexandria between the years 70 and 100.
His feast day is June 10th.