One of the titles used to refer to Jesus in the New Testament is "Son of God."
In the Old Testament, this phrase had a general meaning of "belonging to God." It was applied to the people of Israel in general and especially its rulers (e.g. Ex 4:22; 2 Sa 7:14).
Jesus does not refer to himself as the Son of God in the Gospels, but the term is used in the writings of Paul (e.g. Ro 1:4, 8:31) and in the epistle to the Hebrews (4:14). The Gospel of John refers to Jesus simply as "the Son," which may have a similar meaning.
Paul uses the term for both Jesus Christ and Christians, but distinguishes between the two: Christians become sons of God by adoption, but Jesus is the rightful Son of God by nature. (McGrath, Christian Theology, 327)