Bartholomew is seen in the New Testament only in the lists of the apostles.
Matthew 10:2-3, "These are the names of the twelve apostles: first, Simon (who is called Peter) and his brother Andrew; James son of Zebedee, and his brother John; Philip and Bartholomew; Thomas and Matthew the tax collector; James son of Alphaeus, and Thaddaeus;"
Mark 3:16-19, "These are the twelve he appointed: Simon (to whom he gave the name Peter), James son of Zebedee and his brother John (to them he gave the name Boanerges, which means “sons of thunder”), Andrew, Philip, Bartholomew, Matthew, Thomas, James son of Alphaeus, Thaddaeus, Simon the Zealot and Judas Iscariot, who betrayed him."
Luke 6:13-16, "When morning came, he called his disciples to him and chose twelve of them, whom he also designated apostles: Simon (whom he named Peter), his brother Andrew, James, John, Philip, Bartholomew, Matthew, Thomas, James son of Alphaeus, Simon who was called the Zealot, Judas son of James, and Judas Iscariot, who became a traitor.
Acts 1:13, "When they arrived, they went upstairs to the room where they were staying. Those present were Peter, John, James and Andrew; Philip and Thomas, Bartholomew and Matthew; James son of Alphaeus and Simon the Zealot, and Judas son of James."
Indeed, Nathanael saw greater things. He was one of those to whom Jesus appeared on the shore of the Sea of Tiberias after his resurrection.
John 21:1-14 (Jesus and the miraculous catch of fish), "Afterward Jesus appeared again to his disciples, by the Sea of Galilee. It happened this way: Simon Peter, Thomas (also known as Didymus), Nathanael from Cana in Galilee, the sons of Zebedee, and two other disciples were together. “I’m going out to fish,” Simon Peter told them, and they said, “We’ll go with you.” So they went out and got into the boat, but that night they caught nothing. Early in the morning, Jesus stood on the shore, but the disciples did not realize that it was Jesus. He called out to them, “Friends, haven’t you any fish?” “No,” they answered. He said, “Throw your net on the right side of the boat and you will find some.” When they did, they were unable to haul the net in because of the large number of fish. Then the disciple whom Jesus loved said to Peter, “It is the Lord!” As soon as Simon Peter heard him say, “It is the Lord,” he wrapped his outer garment around him (for he had taken it off) and jumped into the water. The other disciples followed in the boat, towing the net full of fish, for they were not far from shore, about a hundred yards. When they landed, they saw a fire of burning coals there with fish on it, and some bread. Jesus said to them, “Bring some of the fish you have just caught.” So Simon Peter climbed back into the boat and dragged the net ashore. It was full of large fish, 153, but even with so many the net was not torn. Jesus said to them, “Come and have breakfast.” None of the disciples dared ask him, “Who are you?” They knew it was the Lord. Jesus came, took the bread and gave it to them, and did the same with the fish. This was now the third time Jesus appeared to his disciples after he was raised from the dead."
Nathanael Bartholomew, in Hebrew Nathanael means "gift of God." Ever cheerful person is a gift of God to a friendship and Bartholomew means "son of a drill-plougher." A "Nathanael" must also be a "Bartholomew," a man who goes below the surface of things. And a "Bartholomew" must be a "Nathanael," a sunny gift of God that penetrates to the depths of life, but remains on the outside also, so that, once buried in these depths, it does not lose sight of the blue heavens from where it came, where the angels of God ascend and descend.
St Bartholomew is credited with many other miracles having to do with the weight of objects.