Albert Barnes' Notes on the Whole Bible - Isaiah 8:13
Sanctify ... - Regard Yahweh as holy; that is, worship and honor him with pious fear and reverence. Regard him as the source of safety, and the true defense. Ahaz and his people sought for aid from Assyria against the armies of Syria and Samaria. The direction here is rather to seek aid from God.Let him be your fear - Do not be alarmed at what man can do Isaiah 8:12, but fear and honor God. Be afraid to provoke his wrath by looking to other sources of help when his aid only should be sought. read more
Albert Barnes' Notes on the Whole Bible - Isaiah 8:12
Say ye not - Do not join in their purposes of forming a confederacy. Do not unite with the king and the people of Judah in their alarms about the threatened invasion by the kings of Syria and Samaria, and in their purpose to form an alliance with the king of Assyria. The reason why they should not do this, he states in Isaiah 8:13, where he exhorts the nation to put confidence in the Lord rather than in man. There has been, however, great diversity in the interpretation of this passage. The... read more