To eat meat; to refresh and cheer up his depressed spirits, as they used to do at funerals. See Jeremiah 16:5 Ezekiel 24:17. Till the sun be down, i.e. till evening; for then fasting days ended of course.
Related Commentaries of 2 Samuel 3:35
2 Samuel 3:35
35 And when all the people came to cause David to eat meat while it was yet day, David sware, saying, So do God to me, and more also, if I taste bread, or ought else, till the sun be down.