John Gill Commentary 1 Kings 6:12

"Concerning this house which thou art building, if thou wilt walk in my statutes, and execute mine ordinances, and keep all my commandments to walk in them; then will I establish my word with thee, which I spake unto David thy father." — 1 Kings 6:12 (ASV)

[Concerning] this house which you are in building
Or with respect to that, these things are to be said as from the Lord:

if you will walk in my statutes, and execute my judgments, and keep
all my commandments to walk in them ;
even all the laws of God, moral, ceremonial, and judicial; and this respects not only Solomon personally, but his successors, and even all the people of Israel:

then will I perform my covenant with you, which I spoke unto David your
father ;
by Nathan the prophet; not only that he should build an house for God, which should be a settled dwelling place, but that his own house and kingdom should be established for a long time to come, and his posterity should enjoy the presence of God in this house, provided regard was had to the precepts and ordinances of the Lord, (2 Samuel 7:12–16) .