They took Jesus up to Jerusalem to dedicate him to the Lord. On this fifth day in the Octave of Christmas, we are given for our reflection the presentation of Jesus in the temple. We are told that this was done to fulfill the law which required every firstborn son to be dedicated to God by the offering of a sacrifice. Why?
In the book of Exodus, God directs Moses to make it a rule that every male child is to be dedicated to the Lord in remembrance of Israel’s redemption from the Egyptians (cf. Exodus 13:11-16). As such, dedication of a child to God is an act of thanksgiving, a thanksgiving to God for a successful childbirth, and a thanksgiving to God for the gift of a new life in the family. It didn't mean that the child was to be left in the temple (as Samuel was). Rather, it was recognition that a child was a gift from God, and presenting him to God was a way of asking God to continue blessing him even as God had blessed him with life. Moreover, God also directed Moses that the dedication was to be a way of entrusting the ‘redemption/salvation’ of the nation/tribe/family to the first born. It was to be a sign that the responsibility had now been passed to a new generation who would then see to it that just as God had kept the nation safe from its adversary, it was now his turn to carry out this noble responsibility.
Jesus’ dedication, however, was broader than that of a normal first-born. The responsibility that was being put on his shoulders was not only of the family of Mary and Joseph (or of Israel as a nation for that matter), but rather of the universe. He was taking upon himself his Father’s (God) responsibility. He was going to lead creation into the big exodus of slavery to sin in order to transform them into children of God (cf. Romans 6:18). And as it happened in all the other cases, he had to be prepared for such a responsibility as early as possible.