Say ye not. The transition from the singular to the plural is noticeable. It implies that Isaiah did not stand alone, but had followers—a "little flock," it may be—but still enough to give him the support of sympathy (comp.
verse 16). A confederacy; rather, treason, or conspiracy (see 2 Samuel 15:12; 1 Kings 16:20; 2 Kings 11:12; 2 Kings 12:20; Jeremiah 11:9; Ezekiel 22:25, etc.). The command is, not to call a course of conduct treasonable simply because the people generally so call it.
Jeremiah was charged with treason for preaching the hopelessness of offering resistance to Nebuchadnezzar (Jeremiah 20:1; Jeremiah 26:8-11). Those who opposed an Assyrian alliance were probably now taxed with treason.
To all them to whom; rather, everything which. Translate the entire clause thus: Call ye not conspiracy everything which this people shall call conspiracy. Neither fear ye their fear. They feared man (Isaiah 7:2).
Isaiah and his disciples are commanded to fear no one but God.