Charles Spurgeon Commentary Isaiah 44:23

"Sing, O ye heavens, for Jehovah hath done it; shout, ye lower parts of the earth; break forth into singing, ye mountains, O forest, and every tree therein: for Jehovah hath redeemed Jacob, and will glorify himself in Israel." — Isaiah 44:23 (ASV)

Sing, O you heavens, for the LORD has done it: shout, you lower parts of the earth: break forth into singing, you mountains, O forest, and every tree therein: for the LORD has redeemed Jacob, and glorified himself in Israel.

Pardoned sin is enough to make even the rocks sing; mountains, trees, forests, and even the lower parts of the earth, are made to echo with song when sin is blotted out.