Zechariah 6:15

And they [that are] afar off shall come,..... Into the temple; not the material temple; nor is this a prophecy which was fulfilled in Herod, a stranger, repairing that, as Kimchi suggests; but into the spiritual temple, the church; and is a prophecy of the calling of the Gentiles, who are said to be "afar off", Ephesians 2:12, from God; from having his image on them; from subjection to his law; from the knowledge and fear of him; and from communion with him: from Christ; from the knowledge of his person, righteousness, and salvation by him; from love to him, faith in him, and fellowship with him; from the Spirit of God, and from the people of God, and from any solid hope of eternal life: now these being called by grace, and brought to Christ under the drawings of the Father's love, shall come to his church, and join themselves to his people:

and build in the temple of the Lord; upon the foundation Christ; and be useful in building up others, either by private conversation, or by public preaching the word; it is not said, they shall "build the temple of the Lord"; that is Christ's work; but "build in" it:

and ye shall know that the Lord of hosts hath sent me unto you; that is, the Prophet Zechariah, who was sent to the Jews to declare these things to them; or, as the Targum adds, "to prophesy unto you": which they would fully know, and be assured of, when these things should have their accomplishment:

and [this] shall come to pass, if ye will diligently obey the voice of the Lord your God; not that the fulfilment of the above predictions depended upon their obedience; but when they should in the latter day obey the Gospel of Christ, or "the word of the Lord" their "God", as the Targum paraphrases it; then this would come to pass, that they should know that the prophet had his mission from the Lord.