John Gill Bible Commentary

And Hezekiah answered, it is a light thing for the shadow to go down ten degrees,.... That is, it was comparatively so, otherwise to go down ten degrees at once would be extraordinary and miraculous; but that was more agreeable to the nature and course of it to go forward, and so the miracle would be less apparent: nay, but let the shadow return backward ten degrees; which was directly contrary to its natural order and course, whereby the miracle would appear more clear and manifest: these degrees are by some said (x) to be half hours, and not full ones, since it is observed the sun shines not twenty full hours on any dial, unless under the pole; the sun is supposed to have been now at the fifth full hour; the sun was brought back five whole hours, then came forward five, then came forward two degrees, or one hour, to the sixth hour; which made sixteen; then it was six hours to sunset; so that day was prolonged twenty two hours: the Chinese (y) relate, that, in the time of Kingcungus, the planet Mars, for sake of the king, went back three degrees. (x) Weemse's Christ. Synagog. l. 1. c. 6. sect. 6. p. 167. See his Exposition of the Judicial Laws, c. 25. p. 90. &c. (y) Martin. Sinic. Hist. l. 4. p. 138.