Confirm thy words - "Establish" them, by giving a second testimony. Nathan thinks it best to move David's affections first through Bath-sheba, before he comes in to discuss the matter as one of state policy, and to take the king's orders upon it.

Behold, while thou yet talkest there with the king,.... Before, or by the time she could deliver the above words to him, or such as she should think fit to use, to awaken the king to a concern for the interest of her and her son:

I will also come in after thee; directly into the king's chamber:

and confirm thy words; as he could very well do, if he was present as a witness of the oath he had made to her, as well as he could confirm the truth of Adonijah's usurpation; nay, could plead the will and promises of God he had formerly notified to him: or, "fill up thy words" (f), make up what might be wanting in her address to him, in her account of things, or in the arguments used by her; he means, that he would second her in her motion in favour of Solomon, and press the king to take some steps for the security of the succession to him. Nathan knew it was the will of God that Solomon should succeed in the kingdom, he had promised it by him, see 2 Samuel 7:12; yet, as a wise and good man, he thought it right to make use of all proper means to attain the end.

(f) "complebo", Pagninus, Montanus, Vatablus; "explebo", Ar.

While she was still talking to the king, he (Nathan) would come in after her and confirm her words. דּבר מלּא, to make a word full, i.e., not to supply what is wanting, but to make full, like πληροῦν, either to fill by accomplishing, or (as in this case) to confirm it by similar assertion.

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

(h) By declaring such things, as may further the same.

confirm: Heb. fill up

1:11-31 Observe Nathan's address to Bathsheba. Let me give thee counsel how to save thy own life, and the life of thy son. Such as this is the counsel Christ's ministers give us in his name, to give all diligence, not only that no man take our crown, Re 3:11, but that we save our lives, even the lives of our souls. David made a solemn declaration of his firm cleaving to his former resolution, that Solomon should be his successor. Even the recollection of the distresses from which the Lord redeemed him, increased his comfort, inspired his hopes, and animated him to his duty, under the decays of nature and the approach of death.