If harm comes to the root, the rest of the tree feels the effect. (Compare Matthew 3:10; 13:6.) Accordingly, Malachi wrote: “‘The day that is coming will certainly devour them,’ Jehovah of armies has said, ‘so that it will not leave to them either root or bough.’” (Malachi 4:1) The meaning is clear​—complete cutting off. The parents (roots) would be cut off, as well as their offspring (boughs).a This underscores the responsibility parents have toward their minor children; the lasting future of minor children could be determined by their parents’ standing before God.​—1 Corinthians 7:14.

The language at Isaiah 37:31 and Malachi 4:1 draws on the fact that boughs (and the fruit on secondary branches) derive their life from the root. This is a key to understanding how Jesus is the “root of Jesse” and the “root of David.”