The abstract noun "faithfulness" can be translated with an adjective. Alternate translation: "he is faithful to his covenant forever" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
The verb may be supplied from the previous phrase. The abstract noun "truthfulness" can be translated with an adjective. Alternate translation: "his truthfulness endures through all generations" or "he is truthful through all generations" (See: [[rc://en/ta/man/translate/figs-ellipsis]] and [[rc://en/ta/man/translate/figs-abstractnouns]])