John Chrysostom
What does it mean to be a watchman? A sentinel is someone who, positioned on elevated terrain while the soldiers are stationed below, carefully watches for approaching foes and signals the impending attack, preparing them for combat to prevent being easily overwhelmed. Likewise, since we often remain unaware of the dangers that surround us during our earthly existence, God's grace has ordained that the holy prophets, as if standing on a prophetic summit, proclaim in advance the impending judgment of God. This allows us, through sincere repentance and the renewal of our fallen spirits, to proactively avert the divine consequences before they strike. Thus, it is written, I have set you as a watchman for the house of Israel, that you may warn them of the coming disaster, just as one alerts others to the approach of enemies.