It is a light thing - It seemed to Hezekiah comparatively easy that the shadow, which had already begun to lengthen, should merely make a sudden jump in the same direction; but, wholly contrary to all experience that it should change its direction, advancing up the steps again when it had once begun to descend them.
Related Commentaries of 2 Kings 20:10
2 Kings 20:10
10 And Hezekiah answered, It is a light thing for the shadow to go down ten degrees: nay, but let the shadow return backward ten degrees.