How did Thomas Carlyle become friends with Edward Irving?

Thomas Carlyle and Edward Irving became friends while both were working as teachers in Kirkcaldy, Scotland, in 1816.1

Carlyle, who had previously attended the University of Edinburgh, moved to Kirkcaldy to take a teaching position at a school where Irving was also employed. This meeting sparked a deep and lasting bond; Carlyle later remarked that Irving was one of the few men he truly admired and that, without him, he would never have understood the meaning of "communion of man with man". Their friendship persisted even after Irving relocated to London in 1822 to serve as a preacher.12