This [is] the word that the Lord hath spoken
That is, this prophecy now delivered out is what comes from the Lord; it is the word of the Lord, and not of man, and so shall certainly come to pass; when this word was spoken follows: since that time;
from eternity, as some, and so refer it to the decree of God within himself; or from the time that Moab was in being, or a nation, as others; or from the time that Balak hired Balaam to curse Israel, so Jarchi; or rather from the time that the Lord made known his mind and will, concerning this matter, to the prophet Isaiah: for it should be rendered, "this is that word which the Lord spake concerning Moab then" F9; that is, at the time or year in which Ahaz died, ( Isaiah 14:28 ) and is observed, to distinguish it from what the prophet spoke, or was about to speak, now or from this time, concerning him, as in the next verse ( Isaiah 16:14 ) .
F9 So Noldius, Ebr. Concord. Part. p. 473. No. 1586.