John Gill Commentary 2 Samuel 5:19

"And David inquired of Jehovah, saying, Shall I go up against the Philistines? wilt thou deliver them into my hand? And Jehovah said unto David, Go up; for I will certainly deliver the Philistines into thy hand." — 2 Samuel 5:19 (ASV)

And David inquired of the Lord
By Abiathar, and the Urim and Thummim, in the ephod he had on:

saying, shall I go up to the Philistines ?
who by this time were gone from the valley to an higher place, to Mount Perazim, as in (Isaiah 28:21) ;

wilt thou deliver them into my hand ?
here two questions are put together, and an answer returned to both, contrary to a notion of the Jews, (See Gill on 1 Samuel 23:11);

and the Lord said to David, go up, for I will doubtless deliver the
Philistines into thine hand ;
by which oracle he had both the mind of God that he should go up, and was assured of victory.