3 So after searching through all the land of Israel for a fair young girl, they saw Abishag the Shunammite, and took her to the king. 4 Now she was very beautiful; and she took care of the king, waiting on him at all times; but the king had no connection with her.
Matthew Henry's Commentary on 1 Kings 1:3-4
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.