Jerome : (Verse 4, 5.) The earth mourned and declined, and became weak: the world declined, the height of the people of the earth became weak, and the earth was destroyed by its inhabitants. (LXX: The earth mourns, the world is corrupted, the lofty ones of the earth mourn, but the earth acts wickedly due to its inhabitants. God resists the proud and gives grace to the humble (James 4:6). From the first sentence, it is against those who are lofty in the earth, so that everything that is now strong may be weakened because of those who mixed blood with blood, and caused the blood of the slain to cry out to God in a manner similar to Abel's blood (Gen. 4). — Commentary on Isaiah