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 Matt. 3 - that is, probably, until he was about 30 years of age. See Luke 3.

The child grew - Increased in stature and bodily vigor. And waxed strong in spirit - had his understanding Divinely illuminated and confirmed in the truths of God. And was in the deserts - the city of Hebron, the circumjacent hill country, and in or near Nazareth. Till the time of his showing, or manifestation - till he was thirty years of age, before which time the law did not permit a man to enter into the public ministry, Numbers 4:3. See also Luke 3:23.
So much has already been said, by way of practical improvement of the different subjects in this important chapter, as to preclude the necessity of any addition here.

And the child grew, and waxed strong in spirit,.... That is, John, the son of Zacharias and Elisabeth, grew in stature of body, and increased in wisdom and knowledge, and fortitude in his soul:
and was in the deserts; or "desert", as the Syriac, Persic, and Ethiopic versions read; not in the wilderness of Judea, where he came preaching, but either of Ziph or Maon, which were near to Hebron; see 1-Samuel 23:14 he was not brought up in the schools of the prophets, nor in the academies of the Jews, or at the feet of any of their Rabbins and doctors; that it might appear he was not taught and sent of men, but of God: nor did he dwell in any of the cities, or larger towns, but in deserts; partly that he might be fitted for that gravity and austerity of life, he was to appear in; and that it might be clear he had no knowledge of, nor correspondence with Jesus, whose forerunner he was, and of whom he was to bear testimony, till such time he did it; and in this solitude he remained,
till the day of his showing unto Israel; either till the time came that he was to appear before, and be examined by the sanhedrim, that judged of persons fitness and qualifications for the priesthood, in order to be admitted to it; which should have been when he was thirty years of age, but that he was designed for other service; or rather therefore till he appeared in his prophetic office, and showed himself to the people of Israel; to whom he came preaching the doctrine of repentance and remission of sins, administering the ordinance of baptism, giving notice of the near approach of the Messiah, and pointing him out unto the people.

And the child, &c.--"a concluding paragraph, indicating, in strokes full of grandeur, the bodily and mental development of the Baptist; and bringing his life up to the period of his public appearance" [OLSHAUSEN].
in the deserts--probably "the wilderness of Judea" (Matthew 3:1), whither he had retired early in life, in the Nazarite spirit, and where, free from rabbinical influences and alone with God, his spirit would be educated, like Moses in the desert, for his future high vocation.
his showing unto Israel--the presentation of himself before his nation, as Messiah's forerunner.

The child . . . was in the deserts. In the wilderness of Judea where he could have ample opportunity for communion with God.