From the Haydock Bible Commentary
Ver. 41. How can we account for what is related in this verse, that his parents went up every year to Jerusalem, during the childhood of Jesus, when, as we are taught in other parts, his parents did not dare to fix their abode in Jerusalem, for fear of Archelaus: but this, says St. Augustine, will not be very difficult to answer; for, it might be easier for them to ascend up to Jerusalem on these particular occasions, without being noticed in so numerous a crowd, and privately return; though it might not be prudent for them to fix their habitation there, lest they might be too much noticed: and, as no one has yet informed us how long Archelaus continued to reign, what St. Luke relates might have taken place after the death of that prince. (St. Augustine)
Ver. 44. It may be asked how the blessed Virgin and St. Joseph could possibly have come so far without missing him; but we must take notice, that when the people went up to the temple from remote parts of Judea, the men went in one company, and the women in a separate company, whilst the children went in either company indifferently: so that St. Joseph imagined that he was with Mary, his mother, whilst she imagined he was with St. Joseph. (Nicholas of Lyra)
Ver. 49. I must be about the things that are my Father’s? By these words he shewed, that not St. Joseph, but only God, was his father. (Witham)
Ver. 50. They understood not, &c. That is, knew not when, or by what means, Christ designed to make himself known to the world. (Witham)
Ver. 51. Was subject to them. Astonishing humility! which the Son of God was pleased to teach by his example, as also obedience to parents. (Witham) — The evangelist relates nothing of our Saviour from the age of twelve till the age of thirty, except that he was subject to St. Joseph and the blessed Virgin. The divine Spirit shewing by this, that nothing is so great and amiable in Christians, as ready obedience to the directions of their superiors. (Barradius) — All children are hereby taught what subjection and obedience is due from them to their parents.
Ver. 52. Not that he was wiser at any future period of his life, than he was at the moment of his conception, but this is said, because he chose to manifest increasing signs of wisdom as he increased in years. — In the same manner also he increased in grace, by displaying, as he advanced in age, the gifts of grace with which he was endowed; and by this excited men to the praise of God, from the consideration of favours God had bestowed upon him; and thus he conduced to the honour of God, and the salvation of men. (St. Gregory) — The sun, always equally brilliant in itself, is said to increase in splendour, till it has reached its meridian brilliancy