John Gill Commentary Zechariah 1:3

"Therefore say thou unto them, Thus saith Jehovah of hosts: Return unto me, saith Jehovah of hosts, and I will return unto you, saith Jehovah of hosts." — Zechariah 1:3 (ASV)

Therefore say you to them This is an order from the Lord to Zechariah, to say to them, in the name of the Lord:

thus says the Lord of hosts; of the hosts above and below, of angels and of men, of heaven and earth, and all that is therein: this is said, that the greater regard might be had to his words:

turn you to me, says the Lord of hosts; by repentance, and acknowledgment of former sins; by reformation for the future; by attending to the worship and service of God, and seeking to glorify him. So the Targum, "return to my worship": this is not the condition of what follows, but what follows is the motive and encouragement to this:

and I will turn to you, says the Lord of hosts; to dwell among them, manifest himself to and protect them.

Three times the phrase, "the Lord of hosts", is used in this verse: it may be with respect to the three Persons in the Godhead, Father, Son, and Spirit; who manifest themselves to, and take up their abode with, such as love the Lord, and keep his commandments; see (John 14:21) .