This is another gathering song involving John Bell. GA lists him as author of the text and tune. Wild Goose confirms that the tune is a tradition tune from the island of Lewis and Bell adapted it and also that the text also involves his frequent collaborator Graham Maule.
The range is a bit much for groaners like me but the text is exemplary. You can find that text here. Hymnary has details on the tune.
My backing is a slowish C&W version for some reason.