The speaker claims to be a prophet, but the title, "False prophet," makes us doubt him from the start. He says he sees "clear and far," yet what follows is oddly small and domestic. His own trouble, he admits, "made a good sermon," as if his suffering was just material he could turn into a performance for others.
The last two lines are the sharpest. He "leases" a shoulder to his wife, which suggests that his comfort is something he lends out, not freely gives. His lute, a symbol of song and art, gets only "a dull sleep," so it goes unplayed.
The mood is dry, self-mocking, and a little sad. The speaker seems to know he has traded real feeling and creative energy for the role of wise man. Judging by the wording, he can preach about pain but struggles to be present for the people and the music close to him.