Yeshua is not the only King. Verse 16 refers to his Father YHWH.
Let's review the context -
Zechariah 14:
- Behold, the day of the Lord is coming, Zechariah 14:1
The context is about the Day of the Lord.
The Day of the Lord is when Jesus Christ will return with His saints, and pour out the vengeance of God upon the wicked.
15 For this we say to you by the word of the Lord, that we who are alive
and remain until the coming of the Lord will by no means precede those who are asleep. 16 For the Lord Himself will descend from heaven with a shout, with the voice of an archangel, and with the trumpet of God. And the dead in Christ will rise first. 17 Then we who are alive
and remain shall be caught up together with them in the clouds to meet the Lord in the air. And thus we shall always be with the Lord. 18 Therefore comfort one another with these words.But concerning the times and the seasons, brethren, you have no need that I should write to you. 2 For you yourselves know perfectly that
the day of the Lord so comes as a thief in the night. 1 Thessalonians 4:15-5:2
It is the Lord Jesus Christ who will come upon the unprepared, as a thief in the night.
The Day of the Lord is also called the Day of Christ.
Now, brethren, concerning the coming of our Lord Jesus Christ and our gathering together to Him, we ask you, 2 not to be soon shaken in mind or troubled, either by spirit or by word or by letter, as if from us, as though
the day of Christ had come. 2 Thessalonians 2:1-2
Jesus describes this event Himself as He quotes Zechariah to His disciple upon the mount of Olives.
29 “Immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light; the stars will fall from heaven, and the powers of the heavens will be shaken. 30 Then the sign of the Son of Man will appear in heaven, and then all the tribes of the earth will mourn, and
they will see the Son of Man coming on the clouds of heaven with power and great glory. 31 And He will send His angels with a great sound of a trumpet, and they will gather together
His elect from the four winds, from one end of heaven to the other. Matthew 24:29-31
- Thus the Lord my God will come, And all the saints with You. Zechariah 14:5
It is the Lord Jesus that will be coming with the saints.
And then He will send His angels, and gather together His elect from the four winds, from the farthest part of earth to the farthest part of heaven. Mark 13:27
11 Now I saw heaven opened, and behold, a white horse. And He who sat on him was called Faithful and True, and in righteousness He judges and makes war. 12 His eyes were like a flame of fire, and on His head were many crowns. He had a name written that no one knew except Himself. 13 He was clothed with a robe dipped in blood, and His name is called The Word of God. 14 And the armies in heaven, clothed in fine linen, white and clean, followed Him on white horses. 15 Now out of His mouth goes a sharp sword, that with it He should strike the nations. And He Himself will rule them with a rod of iron. He Himself treads the winepress of the fierceness and wrath of Almighty God.16 And He has on His robe and on His thigh a name written:KING OF KINGS AND LORD OF LORDS.
Revelation 19:11-16
The saints clothed in fine linen, white and clean follow Him on white horses.
Jesus is the Lord, who is coming with the saints.
- It shall come to pass in that day that there will be no light;The lights will diminish. 7 It shall be one day Which is known to the Lord—Neither day nor night. But at evening time it shall happen That it will be light. Zechariah 14:6-7
Jesus refers to this phenomenon in the Olivet Discourse.
29 “Immediately after the tribulation of those days
the sun will be darkened, and the moon will not give its light; the stars will fall from heaven, and the powers of the heavens will be shaken. 30 Then the sign of the Son of Man will appear in heaven, and then all the tribes of the earth will mourn, and
they will see the Son of Man coming on the clouds of heaven with power and great glory.
Matthew 24:29-30
It is the Lord Jesus who is coming to earth on the Day of the Lord.
It is the Lord Jesus who is coming with His saints, on that Day.
- And in that day it shall be That living waters shall flow from Jerusalem, half of them toward the eastern sea and half of them toward the western sea;In both summer and winter it shall occur. And the Lord shall be King over all the earth.In that day it shall be—“The Lord is one,” And His name one. Zechariah 14:8-9
Jesus is the Lord who is coming on the Day of the Lord.
Jesus is the Lord who is coming with the saints.
Jesus is the King over all the earth.
Jesus is the Lord of Lords.
Jesus is the Name above every Name.
JLB