Bless … his substance: the noun substance can be used of skill or strength (Good News Translation, and also New International Version “all his skills”); most often it means wealth or property (see 8.18), which is the meaning here. So we may also translate “LORD give the people of this tribe the power to become rich,” or “I pray that the LORD will give you the power to….”

Accept the work of his hands: this does not seem to refer to a single thing, but to everything the Levites do (so Good News Translation, Contemporary English Version).

Crush the loins of his adversaries: it may be that in some languages the equivalent of loins (the sexual organs of a man) in this context is still part of current speech; it certainly is not in English. It is better to use a verb like “defeat” or “destroy,” with the direct object “his [or their, or your] enemies.”

That they rise not again: the enemies are to be defeated and remain powerless forever, never a threat to the people of Israel again. Another way to express this is “so that they [the enemies] will never be able to fight you again.”

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on Deuteronomy. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .