John Calvin on Isaiah 21:16

16. For thus hath the Lord said to me. He adds that this defeat of the Arabians, of which he prophesied, is close at hand; which tended greatly to comfort the godly. We are naturally fiery, and do not willingly allow the object of our desire to be delayed; and the Lord takes into account our weakness in this respect, when he says that he hastens his work. He therefore declares that he prophesies of things which shall happen, not after many ages, but immediately, that the Jews may bear more patiently their afflictions, from which they know that they will be delivered in a short time.

Yet a year according to the years of the hireling. Of the metaphor of “the year of the hireling,” which he adds for the purpose of stating the matter more fully, we have already spoken. {Bogus footnote} It means that the time will not be delayed. The same comparison is used by heathen authors, where they intend to describe a day appointed and desired; as appears from that passage in Horace, “The day appears long to those who must render an account of their work.” {Bogus footnote}