Theophylact of Ohrid

"But they did not understand" what He said to them, for this was a mystery.

Commentary on Luke ↗

Bede

And they did not understand the word that he spoke to them. And he went down with them, and came to Nazareth, and was subject to them. How much an example of piety and humility in the Lord! His parents did not understand the word that he spoke to them about his divinity, and yet he, not ungrateful for their human diligence towards him, descended to where they commanded, and was subject to them. For what would the teacher of virtue be if he did not fulfill the duty of piety? …

On the Gospel of Luke ↗

Bonaventure

And because the word was hidden, it is added: And they did not understand: First Corinthians 2: "We speak wisdom hidden in mystery"; and Tobit 12: "It is good to hide the secret of a king." In this, however, that Christ, when he was corrected, humbly excused himself, and when he was invited by his Mother to perform a miracle, responded harshly, he gave us an example and pattern of humility, so that we should prefer to be corrected rather than praised: Ecclesiastes 7: "It is better to be corrected by a wise man than to be deceived by …

Commentary on Luke, Chapter 2 ↗