Warning: please do not assume the references are in a chronological order. It is up to YOU to read all things that pertains to the references. That means the chapter.

Search hits on the word "Mark" in Revelations:

Rv:13:16: And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads:

Rv:13:17: And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.

Rv:14:9: And the third angel followed them, saying with a loud voice, If any man worship the beast and his image, and receive his mark in his forehead, or in his hand,

Rv:14:11: And the smoke of their torment ascendeth up for ever and ever: and they have no rest day nor night, who worship the beast and his image, and whosoever receiveth the mark of his name.

Rv:15:2: And I saw as it were a sea of glass mingled with fire: and them that had gotten the victory over the beast, and over his image, and over his mark, and over the number of his name, stand on the sea of glass, having the harps of God.

Rv:16:2: And the first went, and poured out his vial upon the earth; and there fell a noisome and grievous sore upon the men which had the mark of the beast, and upon them which worshipped his image.

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.

Rv:20:4: And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years.

Search hits on the word "Mark" in Ezekiel:

Ezek: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.

Ezek:9:6: Slay utterly old and young, both maids, and little children, and women: but come not near any man upon whom is the mark; and begin at my sanctuary. Then they began at the ancient men which were before the house.

Ezek:44:5: And the LORD said unto me, Son of man, mark well, and behold with thine eyes, and hear with thine ears all that I say unto thee concerning all the ordinances of the house of the LORD, and all the laws thereof; and mark well the entering in of the house, with every going forth of the sanctuary.

As you can see in Revelations the reader is programmed to thank that any person that receives a mark on the forehead or on the hand are servants of what they call the beast. I suspect that they added hand due to:

Ex:13:9: And it shall be for a sign unto thee upon thine hand, and for a memorial between thine eyes, that the LORD's law may be in thy mouth: for with a strong hand hath the LORD brought thee out of Egypt.

Ex:13:16: And it shall be for a token upon thine hand, and for frontlets between thine eyes: for by strength of hand the LORD brought us forth out of Egypt.

With these statements it is unclear where the mark will be. To cover all possibilities the writers of Revelations simply kept both possible locations of the mark. As you can clearly see in Ezekiel, God causes a people that feel sorrow and grief, due to the abominations of the people, to receive a mark. The abominations are anything that causes the people to commit what God has declared a sin. I suspect the main thing is their worshiping and servicing of no gods. I suspect this because of what Ezekiel calls the vision:

Ezek:8:3: And he put forth the form of an hand, and took me by a lock of mine head; and the spirit lifted me up between the earth and the heaven, and brought me in the visions of God to Jerusalem, to the door of the inner gate that looketh toward the north; where was the seat of the image of jealousy, which provoketh to jealousy.

Remember what God said makes Him jealous:

Ex:20:5: Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me;

Ex:34:14: For thou shalt worship no other god: for the LORD, whose name is Jealous, is a jealous God:

So know we see in Ezekiel God causes all the people that serve God and God only to receive a mark on their foreheads. But yet in Revelations they call it the mark of the beast. Both of these visions are visions of the time period known as Judgement Day. Neither one has yet occurred. I have yet to meat a people with a God given mark on their forehead. The only marks I have seen are man made. So if you adhere to the OT and the specific actions and sayings of God, you will understand the mark. If you adhere to the NT, you will understand the mark as being the mark of an evil people or servants of the beast. Ministers and servants of Jesus will use this part of Revelations to deceive a many of people into thanking the true people that have found favor in the eyes of God are evil. They will say it is the mark of the beast but all one has to do is be aware of the specific saying and actions of Lord God of Israel. This makes it much, much more difficult for the deceiver to deceive. This is one of the studies that allows me to see that the NT is indeed a Book for the Adversaries of the people of God. In this study they actually are calling God or His Anointed, the beast. I suspect we will receive the mark when we pass under the rod:

Ezek:20:37: And I will cause you to pass under the rod, and I will bring you into the bond of the covenant:

I suspect that in the time period known as Judgement Day the Anointed one will call to all people to come and be judged. This judgement will be done by passing under a rod and or the seven eyes that are upon the precious stone that the Anointed one will find or be given. When the people pass under the rod and receive a mark in the forehead they will be considered a part of the new Israel. It means they have been accepted and Judged in the eyes of God. Their new nationality will be Jerusalem of old. They will be Gods people. The people that pass under the rod and are consumed by the fire, we will know they and their religious beliefs failed in the eyes of God. The people that avoid Judgement will suffer what we call natural disasters. I suspect the time period known as Judgment Day is actually a time that covers an unknown number of years. You have to realize an entire nation has to be rebuilt.

In Revelations there is more writings about a mark:

Rv: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:9:4: And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree; but only those men which have not the seal of God in their foreheads.

Rv:13:16: And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or 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:20:4: And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands; and they lived and reigned with Christ a thousand years.

Rv:22:4: And they shall see his face; and his name shall be in their foreheads.

Rv:14:9: And the third angel followed them, saying with a loud voice, If any man worship the beast and his image, and receive his mark in his forehead, or in his hand,

Rv:17:5: And upon her forehead was a name written, MYSTERY, BABYLON THE GREAT, THE MOTHER OF HARLOTS AND ABOMINATIONS OF THE EARTH.