2 Samuel 10:19
And when all the kings that were servants to Hadarezer saw that they were smitten before Israel, they made peace with Israel, and served them. So the Syrians feared to help the children of Ammon any more. And when all the kings that were servants to Hadarezer saw that they were smitten before Israel, they made peace with Israel, and served them. So the Syrians feared to help the children of Ammon any more.
The verse records the outcome of a vast coalition of the surrounding nations between the Euphrates River and the Mediterranean Sea with Ammon against David's kingdom. That coalition was wholly unprovoked by David and sprang from jealousy of his increasing power. In the second Syrian campaign the king of Syria gathered an immense army and David took the field in person.
By the blessing of God David inflicted a defeat so disastrous that these were the greatest wars and victories of his reign and produced the most extensive additions to his power. The smitten kings, the Syrians from Lebanon to the Euphrates, gave up the war, made peace with Israel, submitted and became tributary and served them, and feared to help the children of Ammon any more. David then pushed the war against the Ammonites with vigor until their strongholds fell and the whole region came under the dominion of Israel.