Though its root grow old in the earth: the poet has in mind the stump of the tree dying and with no new shoots coming up because of lack of water, as becomes clear in verse 9. Verse 8 is related to verse 7 as something unexpected in the light of what was said in verse 7, and the relationship may be expressed in English by such logical connectors as “Even though” or “In spite of the fact.” Verse 7 spoke of the tree and the new shoots above ground, and verse 9 speaks of the stump of the tree and the roots beneath the ground. In the earth in line a is parallel with in the ground or “dust” in line b. In typical fashion the poet shifts from the larger image earth to the smaller ground.

And its stump die in the ground: die in the ground in this context means to rot in the ground.

Quoted with permission from Reyburn, Wiliam. A Handbook on Job. (UBS Helps for Translators). New York: UBS, 1992. For this and other handbooks for translators see here .