Take a look at Psalm 29
 
 
"Give unto the Lord, O you might ones,
   Give unto the Lord glory and strength.
Give unto the Lord the glory due His name;
Worship the Lord in the beauty of holiness.
 
    The voice of the Lord is over the waters;
The God of glory thunders;
The Lord is over many waters.
The voice of the Lord is powerful;
The voice of the Lord is full of majesty.
 
The voice of the Lord breaks the cedars,
Yes,the Lord splinters the cedars of Lebanon.
He makes them also skip like a calf.
Lebanon and Sirion like a young wild ox.
The voice of the Lord divides the flames of fire.
 
The voice of the Lord shakes the wilderness;
The Lord shakes the Wilderness of Kadesh.
The voice of the Lord makes the deer give birth,
And strips the forests bare;
And in His temple everyone says "Glory!"
 
The Lord sat enthroned at the Flood,
and the Lord sits as King forever.
The Lord will give strength to His people;
The Lord will bless His people with peace."
 
 
 
 
My footnote on Psalm 29:7 says this:
 
This psalm traditionally is recited in synagoges on the Day of Pentecost and refers to the phenomena that occurred in Acts 2:1-4; wind and divided flames of fire.
 
Notes on Psalm 29:9 says this:
 
The thunder makes the deer give birth prematurely. But in the temple of God there is a vantage point where all in safety and security can see the awesome power of God and respond with applauding shouts of GLORY.
 
Now lets review Hebrews 12.
 
"For you have not come to the mountain that may be touched and that burned with fire, and to blackness and darkness and tempest,
    and the sound of a trumpet and the voice of words,s o that those who heard it begged that the word should not be spken to them anymore.
    (For they could not endure what was commanded: "And if so much as a beast touches the mountain, it shall be stoned or shot with an arrow."
    And so terrifying was the sight that Moses said, "I am exceedingly afraid and trembling.")
    But you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, to an innumerable company of angels.
    to the general assembly and church of the firstborn who are registered in heaven, to God the Judge of all, to the spirits of just men made perfect,
    to JESUS the Mediator of the new covenant, and to the blood of sprinking that speaks better things than that of Abel.
     See that you do not refuse HIm who speaks. For if they did not escape who refused Him who spoke on earth, much more shall we not escape if we turn away fromHim who speaks from heaven,
   whose voice then shook the earth;  but now He has promised, saying "Yet once more I shake not only the earth, but also heaven."
    Now this "Yet once more,"  indicates the removal of those things that are being shaken, as of things that are made, that the things which cannot be shaken may remain.
     Therefore, since we are receiving a kingdom which cannot be shaken, let us have grace, by which we may serve God acceptably with reverence and godly fear."
 
Why did God bring Israel out of Egypt??? So they would be able to tabernacle with Him in the Wilderness and serve Him.
 
We see the Voice of the Lord equated to a TRUMPET. His voice in Hebrews says "whose voice then shook the earth"  This also is Pentecost.
 
This is what I think. I believe that the "removal" of things that can be shaken versus those which cannot speak of a separation. Possibly the Rapture of the church.
 
Where does John 5 fit in here and the feast mentioned?  I believe this is Rosh ha Shanah. This was given to Israel as a statute forever. (Psalm 81:3)  This is significant I believe to the TRUMPET sounding for Israel for a "holy convocation" (i.e. regathering or making aliyah to Israel).
 
This seems to follow in line with what will happen next.

John 5:43 says,
"I have come in My Father's name, and you do not receive Me; if another comes in his own name, him you will receive."   (speaking of antichrist)
 
Israel's progression is gradual. See Ezekiel 37, nevertheless, Jesus will turn his attention to National Israel at the beginning of their 39th year from the generation from 1967.
 
This is a possible scenario of upcoming events