The man - A "man." Probably an angel different from "the man" who had hitherto accompanied the seer. That angel guided, measured, and explained; this is present only to guide.

And I heard him speaking unto me out of the house,.... The holy place, the prophet being in the inward court: this is Jehovah the Father, the God of Israel, whose glory entered into it; who utters his voice out of Zion; who speaks in his church by his word, and the ministers of it; and which is to be heard and regarded, not as the word of man, but as the word of God:
and the man stood by me: whom he saw at first with a measuring line in his hand, Ezekiel 40:3, and with whom he had been all along, and had seen him measure the house, and all belonging to it: he stood by him as the Mediator between God and him; as the medium of communion with him; as the advocate with the Father: he stood by him to interpret what was said to him; to guide him further into the knowledge of divine things; to assist him, protect and defend him, to continue him in fellowship with God, and to preserve him in grace to glory. Here is an appearance of the three Persons in the Godhead; the Father speaking to the prophet out of the house; the Son in human form standing by him; and the Spirit of the Lord, who had took him up from the ground, and had brought him into the inner court.

the man--who had been measuring the buildings (Ezekiel 40:3).

The man - Christ. Stood - To encourage, and strengthen him.