How do we know that God's judgment is for all flesh?

Isaiah 40:6 states that 'all flesh is grass,' providing a vivid picture of humanity's fleeting nature and ultimate accountability before God. This metaphor emphasizes the transient worth of mankind in contrast to the eternal Word of God, which will stand forever. The judgment applies universally, as all have sinned and fall short of the glory of God. Therefore, recognizing our position as 'grass' in the sight of God leads us to understand our need for Christ, who took upon Himself the judgment that we rightfully deserve, ensuring the salvation of His people.