“By this therefore shall the iniquity of Jacob be purged; and this is all the fruit to take away his sin; when he maketh all the stones of the altar as chalkstones that are beaten in sunder, the groves and images shall not stand up.”
King James Version (KJV)
27:9 By this - By this manner of God's dealing with them. When - Which sin of Jacob's shall be purged, when he shall truly repent of all his sins, and especially of his idolatry. Altar - Their idolatrous altars. Possibly he may say the altar, with respect to that particular altar, which Ahaz had set upon the place of God's own altar; and this prophecy might be delivered in Ahaz's time, while that altar stood. Chalk - stones - When he shall break all those goodly altars in pieces. Not stand - Shall be thrown down with contempt.