John Gill Commentary 2 Samuel 2:17

"And the battle was very sore that day: and Abner was beaten, and the men of Israel, before the servants of David." — 2 Samuel 2:17 (ASV)

And there was a very sore battle that day
When the twenty four men fell together, and no decision could be made thereby, or any triumph on either side, both armies drew up in battle array, and fought very furiously:

and Abner was beaten, and the men of Israel, before the servants of
David ;
the army under him had the worst of it, and were routed, and obliged to flee before the army of David under the command of Joab.