Theophylact of Ohrid
Catena Aurea · Lukasevangelium 1
And the child grew, and waxed strong in spirit, and was in the deserts till the day of his shewing unto Israel.
Or, he was in the deserts that he might be brought up beyond the reach of the malice of the multitude, and not be afraid of man. For if he had been in the world, perchance he had been corrupted by the friendship and conversation of the world. And secondly, that he who was to preach Christ might also be esteemed trust-worthy. But he was hid in the desert until it pleased God to shew him forth to the people of Israel, as it follows, till the day of his shewing forth to Israel.