The writer uses a question to request the Lord to be faithful to his covenant with David. Alternate translation: "Lord, be faithful to your covenant with David as you have been in the past" (See: [[rc://en/ta/man/translate/figs-rquestion]])
The abstract nouns "acts" and "faithfulness" can be translated with a verb and an adverb. Alternate translation: "the things that you did before that showed that you are faithful to your covenant" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])