11 Now King David was old, advanced in years; and they put covers on him, but he could not get warm. 2 Therefore his servants said to him, "Let a young woman, a virgin, be sought for our lord the king, and let her stand before the king, and let her care for him; and let her lie in your bosom, that our lord the king may be warm." 3 So they sought for a lovely young woman throughout all the territory of Israel, and found Abishag the Shunammite, and brought her to the king. 4 The young woman was very lovely; and she cared for the king, and served him; but the king did not know her.
Matthew Henry's Commentary on 1 Kings 1:1-4
Commentary on 1 Kings 1:1-4
(Read 1 Kings 1:1-4)
We have David sinking under infirmities. He was chastised for his recent sins, and felt the effects of his former toils and hardships.