And the child, etc. - “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” (Mat 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.