Genesis 19:38 New International Version (NIV)

³⁸ The younger daughter also had a son, and she named him Ben-Ammi^[a]; he is the father of the Ammonites^[b] of today.

1 Samuel 11:1-11 New International Version (NIV)

Saul Rescues the City of Jabesh

11 Nahash^[a] the Ammonite went up and besieged Jabesh Gilead. And all the men of Jabesh said to him, “Make a treaty with us, and we will be subject to you.”

² But Nahash the Ammonite replied, “I will make a treaty with you only on the condition that I gouge out the right eye of every one of you and so bring disgrace on all Israel.”

³ The elders of Jabesh said to him, “Give us seven days so we can send messengers throughout Israel; if no one comes to rescue us, we will surrender to you.”

⁴ When the messengers came to Gibeah of Saul and reported these terms to the people, they all wept aloud. ⁵ Just then Saul was returning from the fields, behind his oxen, and he asked, “What is wrong with everyone? Why are they weeping?” Then they repeated to him what the men of Jabesh had said.

⁶ When Saul heard their words, the Spirit of God came powerfully upon him, and he burned with anger. ⁷ He took a pair of oxen, cut them into pieces, and sent the pieces by messengers throughout Israel, proclaiming, “This is what will be done to the oxen of anyone who does not follow Saul and Samuel.” Then the terror of the Lord fell on the people, and they came out together as one. ⁸ When Saul mustered them at Bezek, the men of Israel numbered three hundred thousand and those of Judah thirty thousand.

⁹ They told the messengers who had come, “Say to the men of Jabesh Gilead, ‘By the time the sun is hot tomorrow, you will be rescued.’” When the messengers went and reported this to the men of Jabesh, they were elated. ¹⁰ They said to the Ammonites, “Tomorrow we will surrender to you, and you can do to us whatever you like.”

¹¹ The next day Saul separated his men into three divisions; during the last watch of the night they broke into the camp of the Ammonites and slaughtered them until the heat of the day. Those who survived were scattered, so that no two of them were left together.

2 Samuel 10 New International Version (NIV)

David Defeats the Ammonites

10 In the course of time, the king of the Ammonites died, and his son Hanun succeeded him as king. ² David thought, “I will show kindness to Hanun son of Nahash, just as his father showed kindness to me.” So David sent a delegation to express his sympathy to Hanun concerning his father.

When David’s men came to the land of the Ammonites, ³ the Ammonite commanders said to Hanun their lord, “Do you think David is honoring your father by sending envoys to you to express sympathy? Hasn’t David sent them to you only to explore the city and spy it out and overthrow it?” ⁴ So Hanun seized David’s envoys, shaved off half of each man’s beard, cut off their garments at the buttocks, and sent them away.

⁵ When David was told about this, he sent messengers to meet the men, for they were greatly humiliated. The king said, “Stay at Jericho till your beards have grown, and then come back.”

⁶ When the Ammonites realized that they had become obnoxious to David, they hired twenty thousand Aramean foot soldiers from Beth Rehob and Zobah, as well as the king of Maakah with a thousand men, and also twelve thousand men from Tob.

⁷ On hearing this, David sent Joab out with the entire army of fighting men. ⁸ The Ammonites came out and drew up in battle formation at the entrance of their city gate, while the Arameans of Zobah and Rehob and the men of Tob and Maakah were by themselves in the open country.

⁹ Joab saw that there were battle lines in front of him and behind him; so he selected some of the best troops in Israel and deployed them against the Arameans. ¹⁰ He put the rest of the men under the command of Abishai his brother and deployed them against the Ammonites. ¹¹ Joab said, “If the Arameans are too strong for me, then you are to come to my rescue; but if the Ammonites are too strong for you, then I will come to rescue you. ¹² Be strong, and let us fight bravely for our people and the cities of our God. The Lord will do what is good in his sight.”

¹³ Then Joab and the troops with him advanced to fight the Arameans, and they fled before him. ¹⁴ When the Ammonites realized that the Arameans were fleeing, they fled before Abishai and went inside the city. So Joab returned from fighting the Ammonites and came to Jerusalem.

¹⁵ After the Arameans saw that they had been routed by Israel, they regrouped. ¹⁶ Hadadezer had Arameans brought from beyond the Euphrates River; they went to Helam, with Shobak the commander of Hadadezer’s army leading them.

¹⁷ When David was told of this, he gathered all Israel, crossed the Jordan and went to Helam. The Arameans formed their battle lines to meet David and fought against him. ¹⁸ But they fled before Israel, and David killed seven hundred of their charioteers and forty thousand of their foot soldiers.^[a] He also struck down Shobak the commander of their army, and he died there. ¹⁹ When all the kings who were vassals of Hadadezer saw that they had been routed by Israel, they made peace with the Israelites and became subject to them.

So the Arameans were afraid to help the Ammonites anymore.