Then King David went in and sat before the LORD and said, “Who am I, O Lord GOD, and what is my house, that you have brought me thus far?
We have here the solemn address David made to God, in answer to the gracious message God had sent him. We are not told what he said to Nathan; no doubt he received him very kindly and respectfully as God's messenger. But his answer to God he took himself, and did not send by Nathan.
Commenting on 2 Samuel 7:18-29
Then went King David in,.... Into the tabernacle where the ark was, which he had prepared for it, Sa2 6:17, and sat before the Lord; before the ark, the symbol of his presence, and prayed, and gave thanks, as follows: from whence it appears that a sitting posture was sometimes used in prayer, of which we have other instances, Exo 17:11.
DAVID'S PRAYER AND THANKSGIVING. (Sa2 7:18-29) Then went king David in, and sat before the Lord--Sitting was anciently an attitude for worship (Exo 17:12; Sa1 4:13; Kg1 19:4). As to the particular attitude David sat, most probably, upon his heels. It was the posture of the ancient Egyptians before the shrines; it is the posture of deepest respect before a superior in the East.