Here the word "Oh" is used to show that the writer has a strong desire for people to praise Yahweh. The abstract noun "faithfulness" can be translated with an adjective. See how you translated this in [Psalms 107:8](../107/008.md). Alternate translation: "Let people praise Yahweh because he is faithful to his covenant" or "People should praise Yahweh because he is faithful to his covenant" (See: [[rc://en/ta/man/jit/figs-exclamations]] and [[rc://en/ta/man/jit/figs-abstractnouns]])