The remark may refer to some earlier period in the reign of Ahaz, before the capture of Damascus.
They advanced against Ahaz, and overran his helpless country.
To convince him of the truth of this he requested Ahaz to demand a sign.
Yet let not Ahaz exult too much in the immediate deliverance!
So perhaps, for the same reason, JehoAhaz was shortened into Ahaz.
No doubt these proceedings helped to heighten the unpopularity of Ahaz.
Behold, I will bring again the shadow of the degrees, which is gone down in the sun-dial of Ahaz ten degrees backward.
Ahaz may have had this lesson impressed on his mind by his visit to Tiglath-Pileser.
This probably necessitated the construction of a new staircase, which would naturally be called the staircase of Ahaz.
If Ahaz had any conscience left, we can imagine the effect of this upon him.