Books of Ezekiel / Revelation Comparison SERIES: The seal on the Saint's foreheads

And, behold, six men came from the way of the higher gate, 

which lieth toward the north, 

and every man a slaughter weapon in his hand; 

and one man among them was clothed with linen, with a writer's inkhorn by his side: and they went in, and stood beside the brasen altar.
And the glory of the God of Israel was gone up from the cherub, whereupon he was, to the threshold of the house. 

And he called to the man clothed with linen, 

which had the writer's inkhorn by his side; 

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.
Ezekiel 9:2-5

And I saw another angel ascending from the east,

having the seal of the living God: 

and he cried with a loud voice to the four angels,

to whom it was given to hurt the earth and the sea, 

Saying, Hurt not the earth, neither the sea, nor the trees, till we have sealed the servants of our God in their foreheads.
Revelation 7:2,3