45 And not finding him, they returned into Jerusalem, seeking him. 46 And it came to pass, that, after three days, they found him in the temple, sitting in the midst of the doctors, hearing them, and asking them questions.
Origen: Learn where those who seek Him find Him, not every where, but in the temple. And do thou then seek Jesus in the temple of God. Seek Him in the Church, and seek Him among the masters who are in the temple. For if thou wilt so seek Him, thou shalt find Him. They found Him not among His kinsfolk, for human relations could not comprehend the Son of God; not among His acquaintance, for He passes far beyond all human knowledge and understanding. Where then do they find Him? In the temple!
Ambrose: After three days He is found in the temple, that it might be for a sign, that after three days of victorious suffering, He who was believed to be dead should rise again, and manifest Himself to our faith, seated in heaven with divine glory.
Origen: Because moreover He was the Son of God, He is found in the midst of the doctors, enlightening and instructing them. But because He was a little child, He is found among them not teaching but asking questions. . . . And this He did as a duty of reverence, that He might set us an example of the proper behavior of children, though they be wise and learned, rather to hear their masters than teach them, and not to vaunt themselves with empty boasting. But He asked not that He might learn, but that asking He might instruct. For from the same source of learning is derived both the power of asking and answering wisely.
Bede: To show that He was a man, He humbly listened to the masters; but to prove that He was God, He divinely answered those who spoke.
47 And all that heard him were astonished at his wisdom and his answers.
Greek Expositor: He asks questions with reason, He listens with wisdom, and answers with more wisdom, so as to cause astonishment.
Chrysostom: The Lord truly did no miracle in His childhood, yet this one fact St. Luke mentions, which made men look with wonder upon Him.
Bede: From His tongue there went forth divine wisdom, while His age exhibited man’s helplessness, and hence the Jews, amid the high things they hear and the lowly things they see, are perplexed with doubts and astonishment. But we can in no wise wonder, knowing the words of the Prophet, that thus unto us a Is Child is born, that He abideth the mighty God. [Isa 9:6]
Scripture from the Douay-Rheims Bible. Commentary from St. Thomas Aquinas, Catena Aurea, Vol. III (London: Rivington, 1843).