Waxed strong in spirit - That is, in courage, understanding, and purposes of good, fitting him for his future work. The word “wax” means to “increase, to grow,” from an old Saxon word.
In the deserts - In Hebron, and in the hill country where his father resided. He dwelt in obscurity, and was not known publicly by the people.
Until the day of his showing - Until he entered on his public ministry, as recorded in Matthew 3 - that is, probably, until he was about 30 years of age. See Luke 3.