In this context the term "God" indicates authority, not ontology. The son is God, not because he is made of "God-Stuff"; he is God because he has been appointed to sit the father's right hand (authority).
The context is the Father speaking to the Son.
But
to the Son He says:
“Your throne, O God, is forever and ever;
A scepter of righteousness is the scepter of Your kingdom.
You have loved righteousness and hated lawlessness;
Therefore God, Your God, has anointed You
With the oil of gladness more than Your companions.”
And: “
You, LORD, in the beginning laid the foundation of the earth,
And the heavens are the work of Your hands. Hebrews 1:8-10
The Son, YHWH the LORD God created the heavens and the earth.
Who comes on the Day of the LORD (YHWH) ; the Son or the Father?
For you yourselves know perfectly that
the day of the Lord so comes as a thief in the night. 1 Thessalonians 5:2
Behold,
the day of the LORD is coming,
And your spoil will be divided in your midst.
For I will gather all the nations to battle against Jerusalem;
The city shall be taken,
The houses rifled,
And the women ravished.
Half of the city shall go into captivity,
But the remnant of the people shall not be cut off from the city.
Then the LORD will go forth
And fight against those nations,
As He fights in the day of battle.
And in that day His feet will stand on the Mount of Olives,
Which faces Jerusalem on the east.
And the Mount of Olives shall be split in two,
From east to west,
Making a very large valley;
Half of the mountain shall move toward the north
And half of it toward the south.
Then you shall flee through My mountain valley,
For the mountain valley shall reach to Azal.
Yes, you shall flee
As you fled from the earthquake
In the days of Uzziah king of Judah.
Thus the LORD my God will come,
And all the saints with You.
Zechariah 14:1-5
Who is coming on
the Day of the LORD (YHWH) with the saints; the Father or the Son?
Now Enoch, the seventh from Adam, prophesied about these men also, saying, “Behold,
the Lord comes with ten thousands of His saints, Jude 1:14
Now, brethren, concerning
the coming of our Lord Jesus Christ and our gathering together to Him, we ask you, 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
The Day of the LORD (YHWH) is the the Day of Christ.
The LORD Jesus Christ is YHWH the LORD God.