Ezekiel 9:4 And the LORD said unto him, Go through the midst of the city, through the midst of Jerusalem, and SET A MARK UPON THE FOREHEADS of the men that sigh and that cry for all the abominations that be done in the midst thereof.

This man clothed with linen had the task to set a "Mark" upon the forehead of the righteous men living in Jerusalem, by his side was a scribe's inkhorn to also write their names in the Book of Life.

Ezekiel 10:2 And he spake unto the man clothed with linen, and said, Go in between the wheels, even under the cherub, and FILL THINE HAND WITH COALS OF FIRE from between the cherubims,
AND SCATTER THEM OVER THE CITY. And he went in my sight.

Yahshua (Jesus) commanded those he had chosen that they should not depart from Jerusalem but wait for the promise of the Father. He also explained to them, it is expedient for him to go away, so he ascended to heaven even to the throne of God, into the midst of the Cherubims where he took and scattered the Fire over Jerusalem.

Acts 2:2 And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting.
3: And there appeared unto them CLOVEN TONGUES LIKE AS OF FIRE, and it sat upon each of them.
4: And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.

These men were marked by the Fire of the Holy Spirit coming from the throne of God, they received the Comforter whom the Lord Jesus Christ said He would send unto them from the Father:

"even the Spirit of truth, which proceedeth from the Father".

The Apostle Paul refers to the Mark of God in these terms:

"Now he which establisheth us with you in Christ, and hath ANOINTED us, is God; Who hath also SEALED us, and given the earnest of the Spirit in our hearts."

The Apostle Paul wrote in the Epistle to the Ephesians:

"ye were SEALED with that holy Spirit of promise"

And he also wrote:

Ephesians 1: 13: And you also were included in Christ when you heard the word of truth, the gospel of your salvation.
Having believed, you were MARKED in him with a SEAL, the promised Holy Spirit,
14: who is a deposit guaranteeing our inheritance until the redemption of those who are God’s possession - to the praise of his glory. (New International Version)

As you just read the Apostle Paul spoke of the elect, who received the spiritual mark on their forehead, as sealed by the Holy Spirit. The Apostle John also in the book of Revelation spoke of the Holy Spirit as the Seal of God:

Revelation 7:3
Saying, Hurt not the earth, neither the sea, nor the trees, till we have sealed the servants of our God in their foreheads.

Rv:14:1: And I looked, and, lo, a Lamb stood on the mount Sion, and with him an hundred forty and four thousand, HAVING HIS FATHER'S NAME WRITTEN IN THEIR FOREHEADS.

Rv:22: 3: And there shall be no more curse: but the throne of God and of the Lamb shall be in it; and his servants shall serve him:
4: And they shall see his face; and HIS NAME SHALL BE IN THEIR FOREHEADS.

Rv:3:12: Him that overcometh will I make a pillar in the temple of my God, and he shall go no more out: and I WILL
WRITE UPON HIM THE NAME OF MY GOD, AND THE NAME OF THE CITY OF MY GOD, which is new Jerusalem, which cometh down out of heaven from my God: and I WILL WRITE UPON HIM MY NEW NAME.

On the other hand, the Apostle John also warned not to be deceived to receive another Spiritual Mark called the Mark of the Beast.

Rv:19:20: And the beast was taken, and with him the FALSE PROPHET that wrought MIRACLES before him, with which he DECEIVED them that had received THE MARK OF THE BEAST, and them that WORSHIPPED his image. These both were cast alive into a lake of fire burning with brimstone.

By the Jewish religious leaders was accomplished the Sign of the Crucifixion of the Son of God. Filled with the spirit of Antichrist they enticed Judah and Israel into sorcery, spiritual whoredom, doctrines of Devils and the shedding of innocent blood. The Judgment of God over Jerusalem with the Temple and the Cities of Israel was mercilessly executed in 70 AD.

In the Revelation given to the Apostle John there are also warnings to the Seven Churches concerning Balaam, Jezebel, false doctrines, idolatry, unfaithfulness and spiritual fornication. There is nothing new under the sun, Churches of our time with Signs and Wonders are also marking deceived believers with the Mark of the Beast which is the Anointing of Satan.

Related Study:

Computer Chip or Anointed Mark of the Beast
https://www.brighteon.com/8cdda8b9-d6fc-4b50-9b01-1960fbfef6ec