shall the shadow] This was to be an evidence of the suns sudden being in such a degree of heaven, before the accustomed course thereof, or of its sudden starting back so far. And because it was all one with the LORD to do the one or the other, he refers it to Hezekiahs choice, lest he should renew his desire, as Gideon did, Judg. 6. 39. ten degrees] This message might be brought to the king at high noon, when the sun might go forward or backward ten degrees: whence is inferred that the diall here mentioned was divided into twenty four equall parts, each of them being half an hour.