John Wesley on Ezekiel 40:3

A man - The same no doubt that appeared to the prophet, chap.1:26, whose name is the branch, and who builds the temple, Zech 6:12,13, whose colour was like burnished brass; Rev 1:15, which speaks glory and strength. A line - A plumb - line, a mason's line to discover the rectitude of the building, or its defects. In the gate - In the north gate, next toward the east.