“Ah, sword of the LORD, how long till you rest? Return to your sheath; cease and be still.” (Jeremiah 47:6)
The word of the LORD concerning the Philistines: see how the waters are rising in the north; they will overflow the land and everything in it. The people will cry out; all who dwell in the land will wail at the sound of the hooves of galloping steeds, at the noise of enemy chariots and the rumble of their wheels. Fathers will not turn to help their children; their hands will hang limp. Gaza will shave her head in mourning; Ashkelon will be silenced. Ah, sword of the LORD, how long till you rest? Return to your sheath; cease and be still. But how can it rest when the LORD has commanded it, when he has ordered it to attack?
The Catechism draws from Jeremiah's question about the sword the principle of prophetic intercession even for the enemies of Israel: the prophet mourns the destruction of those he was sent to warn (CCC 2635).
Brothers and sisters, ah, sword of the LORD, how long till you rest? Even in the oracle against the enemy, Jeremiah asks for the mercy of its ending. The prophetic heart that announces the sword also prays for its sheathing. Proclaim what God commands and pray for the mercy that limits what God permits. Both belong to the prophetic vocation.
Lord God, how long till the sword rests? Have mercy on all who suffer the consequences of the judgment. Through Christ our Lord. Amen.