Having explained Jesus' origins in the infancy narrative, the Gospel of Matthew next jumps immediately to Jesus' baptism by John and the beginning of his ministry as an adult. The reader is told nothing about his childhood or his life at Nazareth, and consequently nothing about Joseph, who simply vanishes from the scene never to be mentioned again, except for one brief reference: "Where did this man get this wisdom and these mighty works? Is not this the carpenter's son?" (Mt 13:54-55). The question asked has a type of parallel in each of the other Gospels (Mk 6:3; Lk 4:22; Jn 6:42), but none says "carpenter's son." Only Mark 6:3 uses the word "carpenter," but applied to Jesus, without mention of Joseph. It was the natural responsibility of a father to teach his trade to the son he was raising. Besides the title "Son of David," Jesus also receives from Joseph the title "son of the carpenter," adding a concrete human dimension that is part of the mystery of the Incarnation. The son of the carpenter who grew up working at his father's side would necessarily also be known to the people of his hometown as "the carpenter."
The actual Greek word used for Joseph's profession occurs nowhere else in the New Testament apart from these two cases of Matthew and Mark. The word is broader than simply "carpenter," and may be applied to a builder or a worker of any hard material such as stone or metal, thus opening a wide range of possibilities for the type of work that Joseph did.
The passage containing this reference (Mt 13:53-58) indirectly may shed some light on Joseph's disappearance from the scene. It is the only time that this Gospel actually names Jesus as Joseph's "son," and it is the people of Nazareth, "his own country," who refer to him in this way. They are the first to take offense at his teaching, because they are all too aware of his ordinary human upbringing. This would furnish one explanation for Joseph's absence in Jesus' ministry, which begins immediately with a voice from Heaven declaring "This is my beloved Son" (Mt 3:17). It could only cause confusion in people's minds to have Jesus' human father present while he was being revealed as the unique Son of God.
The presence of a human father was necessary for Davidic descent, for protection, affection, and instruction. The years of Jesus' life with Joseph and Mary at Nazareth are not recorded in history. It is reasonable to conclude that, in his human nature, Jesus learned from his parents, as every child must, and that what he learned was evidenced in the human manner in which he expressed his teaching and in the concrete images he used in the parables. Perhaps the very ordinariness of these years, in which nothing special stands out to record, is part of the principal information one needs to know about Jesus' human origins: he became like every other human being. Once Jesus' identity has been firmly established, one is prepared to receive the divine Good News he brings. From the absence of Joseph even when Mary is mentioned in the rest of Gospel, it may be concluded that he had died by the time of the beginning of Jesus' public ministry. No further data is available. The carpenter of Nazareth faithfully and unquestioningly fulfills all that God asks of him, and then just as quietly disappears.
Taken from http://www.osjoseph.org/stjoseph/scripture/part1sec6.php
