Observe how brief is the announcement of the child's birth, important as that was to the father's heart, and how the prophecy lingers on the child's future work, which is important for the world. His name, character, and work in general are first spoken, and then his specific office as the Forerunner is delineated at the close. The name is significant. 'John' means 'The Lord is gracious.' It was an omen, a condensed prophecy, the fulfilment of which stretched beyond its bearer to Him as whose precursor alone was John a token of God's grace.
His character (ver. 15) puts first 'great in the sight of the Lord.' Then there are some whom God recognises as great, small as we all are before Him. And His estimate of greatness is not the world's estimate. How Herod or Pilate or Caesar, or philosophers at Athens, or rabbis in Jerusalem would have scoffed if they had been pointed to the gaunt ascetic pouring out words which they would have thought wild, to a crowd of Jews, and been told that that was the greatest man in the world (except One)! The elements of greatness in the estimate of God which is truth, are devotion to His service, burning convictions, intense moral earnestness, superiority to sensuous delights, clear recognition of Jesus, and humble self-abnegation before Him. These are not the elements recognised in the world's Pantheon. Let us take God's standard.
John was to be a Nazarite, living not for the senses, but the soul, as all God's great ones have to be. The form may vary, but the substance of the vow of abstinence remains for all Christians. To put the heel on the animal within, and keep it well chained up, is indispensable, if we are ever to know the buoyant inspiration which comes from a sacreder source than the fumes of the wine-cup. Like John, we must flee the one if we would have the other, and be 'filled with the Holy Ghost.'
The consequence of his character is seen in his work, as described generally in verse 16. Only such a man can effect such a change, in a time of religious decay, as to turn many to God. It needs a strong arm to check the downward movement and to reverse it. No one who is himself entangled in sense, and but partially filled with God's Spirit, will wield great influence for good. It takes a Hercules to stop the chariot racing down hill, and God's Herculeses are all made on one pattern, in so far that they scorn delights, and empty themselves of self and sense that they may be filled with the Spirit.
John's specific office is described in verse 17, with allusion to the closing prophecy of Malachi. That prophecy had kindled an expectation that Elijah, in person, would precede Messias. John was like a reincarnation of the stern prophet. He came in a similar epoch. His characteristic, like Elijah's, was 'power,' not gentleness. If the earlier prophet had to beard Ahab and Jezebel, the second Elijah had Herod and Herodias. Both haunted the desert, both pealed out thunders of rebuke. Both shook the nation, and stirred conscience. No two figures in Scripture are truer brethren in spirit than Elijah the Tishbite and John the Baptist.
His great work is to go before the Messiah, and to prepare Israel for its King. Observe that the name of the coming One is not mentioned in verse 17. 'Him' is enough. Zacharias knew who 'He' was. But observe, too, that the same mysterious person is distinctly called 'The Lord,' which in this connection, and having regard to the original prophecy in Malachi, can only be the divine name. So, in some fashion not yet made plain, Messiah's advent was to be the Lord's coming to His people, and John was the Forerunner, in some sense, of Jehovah Himself.