Charles Ellicott Commentary 1 Chronicles 17:23

"And now, O Jehovah, let the word that thou hast spoken concerning thy servant, and concerning his house, be established for ever, and do as thou hast spoken." — 1 Chronicles 17:23 (ASV)

Lord. —Samuel adds “God.”

Let the thing ... be established. — Let the word (promise) be upheld, maintained, assured. Samuel has a different verb, “establish you.”