(1) As it is written in the (a) prophets, Behold, (b) I send my messenger (c) before thy face, which shall prepare thy way before thee.
(1) John goes before Christ as it was foretold by the prophets.
(a) This is the figure of speech called metonymy, by which is meant the books of the prophets Malachi and Isaiah.
(b) The prophet uses the present tense when he speaks of a thing to come, as he is as sure of it as if he had already seen it.
(c) A metaphor taken from the practice of kings, who used to have ushers go before them.