Albert Barnes Commentary 2 Samuel 2:27

"And Joab said, As God liveth, if thou hadst not spoken, surely then in the morning the people had gone away, nor followed every one his brother." — 2 Samuel 2:27 (ASV)

Joab’s speech means either, “Unless you had spoken (challenging us to fight, 2 Samuel 2:14), the people would have returned from pursuing their brethren this morning;” or, “If you had not spoken (asking for peace, 2 Samuel 2:26), the people would surely not have ceased the pursuit until the morning.” The latter interpretation is more consistent with Joab’s boastful character.