Isaiah 51:7-16 and preaching prophetic commands

Isaiah 51:7-16 communicates theology in the form of prophetic commands: "fear not..." (cf. Isaiah 51:7, 12, 13).  God's people, of course, are living in a kingdom where the godless rule.  Isaiah 51:7 describes God's people in terms of His righteousness and His laws and this is why we get attacked and criticized. The bulk of the section (Isaiah 51:8-16) explain why we can have courage.  Our Redeemer has incredible power and will redeem us just as He did during the Exodus.  Though Isaiah challenges us with a difficult command, "fear not", the mood of this section is celebratory as seen in Isaiah 51:11.  Most comforting words end the section: "You are my people." (cf. Isaiah 51:16).