After the comfortable promises made to Ahaz as a branch of the house of David, here follow terrible threatenings against him, as a degenerate branch of that house; for though the loving-kindness of God shall not be utterly taken away, for the sake of David and the covenant made with him, yet his iniquity shall be chastened with the rod, and his sin with stripes. Let those that will not mix faith with the promises of God expect to hear the alarms of his threatenings.