The fact that Christ and God are omnipresent is not relevant to the concept of Him returning a second time.
For example that had no bearing on what the angels told the disciples after He was taken up in a cloud when HE ascended back into heaven to be with God the Father.
Acts 1
The former account I made, O Theophilus, of all that Jesus began both to do and teach, 2 until the day in which [
a]He was taken up, after He through the Holy Spirit had given commandments to the apostles whom He had chosen, 3 to whom He also presented Himself alive after His suffering by many [
b]infallible proofs, being seen by them during forty days and speaking of the things pertaining to the kingdom of God.
Jesus Ascends to Heaven
9 Now when He had spoken these things, while they watched, He was taken up, and a cloud received Him out of their sight. 10 And while they looked steadfastly toward heaven as He went up, behold, two men stood by them in white apparel, 11 who also said, “Men of Galilee, why do you stand gazing up into heaven?
This same Jesus, who was taken up from you into heaven, will so come in like manner as you saw Him go into heaven.”
Mark 16:19 So then, after the Lord had spoken to them, He was received up into heaven, and sat down at the
right hand of God.
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Come from where? The highest heaven where He is seated at the right hand of the Power, the Father.
And who comes back? Well scripture reads that everyone in heaven comes back with Christ, including the Father. No one is left behind.
Example
1 Thessalonians 4
The Comfort of Christ’s Coming
13 But I do not want you to be ignorant, brethren, concerning those who have fallen [
b]asleep, lest you sorrow as others who have no hope. 14 For if we believe that Jesus died and rose again,
even so God will bring with Him those who [c]sleep in Jesus.
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 [
d]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.
Matthew 26:64
Jesus said to him, “
It is as you said. Nevertheless, I say to you, hereafter you will see the Son of Man sitting at the
right hand of the Power, and coming on the clouds of heaven.”
Mark 14:62
Jesus said, “I am. And you will see the Son of Man sitting at the
right hand of the Power, and coming with the clouds of heaven.”
Mark 8:38
For whoever is ashamed of Me and My words in this adulterous and sinful generation, of
him the Son of Man also will be ashamed when He comes in the glory of His Father
with the holy
angels.”
Psalm 110 also says the Lord is at His right hand when He comes in the Day of His wrath to execute vengeance and fills the places with dead bodies. So there is never any separation from the Father even as Christ descends from heaven, He never leaves the Father's side, and the Father never leaves Him alone, on His own.
The Lord said to my Lord,
“Sit at My right hand,
Till I make Your enemies Your footstool.”
2 The Lord shall send the rod of Your strength out of Zion.
Rule in the midst of Your enemies!
3 Your people
shall be volunteers
In the day of Your power;
In the beauties of holiness, from the womb of the morning,
You have the dew of Your youth.
4 The Lord has sworn
And will not relent,
“You
are a priest forever
According to the order of Melchizedek.”
5 The Lord is at Your right hand;
He shall [a]execute kings in the day of His wrath.
6
He shall judge among the nations,
He shall fill the places with dead bodies,
He shall [b]execute the heads of many countries.
7 He shall drink of the brook by the wayside;
Therefore He shall lift up the head.