1 Samuel 11:11
And it was so on the morrow, that Saul put the people in three companies; and they came into the midst of the host in the morning watch, and slew the Ammonites until the heat of the day: and it came to pass, that they which remained were scattered, so that two of them were not left together.
Cross-reference
1 Samuel 11:2 gives Nahash's cruel demand to gouge out right eyes, the provocation that led to Saul's decisive victory here.
1 Samuel 30:17 describes David's near-total slaughter of the Amalekites, a parallel military victory with similar total destruction.
1 Samuel 14:47 summarizes Saul's military success against all enemies, with this victory being a key example of that pattern.
In 1 Samuel 14:36, Saul proposes a night pursuit to leave no Philistine alive, mirroring the thorough destruction of the Ammonites here.
Judges 7:16 shows Gideon also dividing his army into three companies, mirroring Saul's identical battle tactic.
Judges 9:43 records Abimelech dividing his forces into three companies, the same military strategy Saul uses here.
Exodus 14:24 describes the Lord attacking in the morning watch, the same time frame as Saul's assault on the Ammonites.
Judges 4:16 describes a similar total victory over enemies, with Barak's pursuit leaving no survivors, echoing the complete rout of the Ammonites here.