Ezekiel 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.
God directs the prophet to fix mind, sight, and hearing upon everything declared about the regulations and statutes of His house, giving close heed both to the ordinances themselves and to the entering in of the house with every going forth from the sanctuary. That charge sets the sanctuary and its service apart as holy, calling for faithfulness on the part of all who serve God while assuring that He Himself will vindicate His honor. In context it draws a line between those who had defiled the sanctuary and the faithful priests who alone are allowed to draw near to minister before God.