1 Kings 1:14

Behold, while thou yet talkest there with the king, I also will come in after thee, and confirm thy words.

Cross-reference

1 Kings 1:17-27 shows the plan from v14 unfolding: Bathsheba speaks to David, then Nathan confirms her words as promised.

1 Kings 1:24 records Nathan's actual confirmation to David, directly fulfilling his stated intention from v14.