Right before King Ahab marches into battle, the true prophet establishes the ultimate test to prove the reliability of his message, letting the outcome of the war serve as the final judge. Micaiah makes a bold declaration to the king of Israel: if the king actually returns from the battlefield alive and in peace, it will serve as undeniable proof that God did not speak through the prophet. Micaiah readily admits that if Ahab survives, his dire warnings were merely his own personal thoughts, completely devoid of divine inspiration.
This dramatic, conditional challenge echoes the words of Moses during the rebellion of Korah. Just as Moses declared that if his challengers were to die a natural death, it would prove God had not sent him [רד״ק], Micaiah places his entire prophetic credibility on the line.
Following this direct challenge to the king, Micaiah turns his attention to the surrounding crowd. Raising his voice so that every person present can hear [מצודת דוד, ביאור שטיינזלץ], he calls out for all the peoples to listen. This address can be understood as a call to all the tribes of Israel, as each individual tribe can be considered a distinct people [מצודת דוד]. Alternatively, it serves as a sweeping call to the immediate gathering or even to the entire world [ביאור שטיינזלץ], utilizing a common expression found throughout biblical language [רד״ק]. Micaiah issues this final, public call with absolute certainty in the truth of God's message. He finishes his warning with the clear, unwavering knowledge that if Ahab proceeds into battle, the king will not return alive [ביאור שטיינזלץ].