17. before him--before "the Lord their God" (Lu 1:16). By comparing this with Mal 3:1 and Isa 40:3, it is plainly "Jehovah" in the flesh of Messiah [CALVIN and OLSHAUSEN] before whom John was to go as a herald to announce His approach, and a pioneer o prepare His way.
      in the spirit--after the model.
      and power of Elias--not his miraculous power, for John did no miracle" (Joh 10:41), but his power "turning the heart," or with like success in his ministry. Both fell on degenerate times; both witnessed fearlessly for God; neither appeared much save in the direct exercise of their ministry; both were at the head of schools of disciples; the success of both was similar.
      fathers to the children--taken literally, this denotes the restoration of parental fidelity [MEYER and others], the decay of which is the beginning of religious and social corruption--one prominent feature of the coming revival being put for the whole. But what follows, explanatory of this, rather suggests a figurative sense. If "the disobedient" be "the children," and to "the fathers" belongs "the wisdom of the just" [BENGEL], the meaning will be, "he shall bring back the ancient spirit of the nation into their degenerate children" [CALVIN, &c.]. So Elijah invoked "the God Abraham, Isaac, and Israel," when seeking to "turn their heart back again" (1Ki 18:36, 37).
      to make ready, &c.--more clearly, "to make ready for the Lord a prepared people," to have in readiness a people prepared to welcome Him. Such preparation requires, in every age and every soul, an operation corresponding to the Baptist's ministry.

JFB.