The story about this war against Syria can be found in  2nd Kings 6:8-23

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Here is the text in the World English Bible (WEB) translation. Its in the public domain so feel free to copy and spread everywhere.

2nd Kings 6

Elisha and the Syrians

⁸ Now the king of Syria was at war against Israel; and he took counsel with his servants, saying, “My camp will be in such and such a place.” ⁹ The man of God sent to the king of Israel, saying, “Beware that you not pass this place, for the Syrians are coming down there.” ¹⁰ The king of Israel sent to the place which the man of God told him and warned him of; and he saved himself there, not once or twice. ¹¹ The king of Syria’s heart was very troubled about this. He called his servants, and said to them, “Won’t you show me which of us is for the king of Israel?” ¹² One of his servants said, “No, my lord, O king; but Elisha, the prophet who is in Israel, tells the king of Israel the words that you speak in your bedroom.” ¹³ He said, “Go and see where he is, that I may send and get him.” He was told, “Behold, he is in Dothan.”

¹⁴ Therefore he sent horses, chariots, and a great army there. They came by night and surrounded the city. ¹⁵ When the servant of the man of God had risen early and gone out, behold, an army with horses and chariots was around the city. His servant said to him, “Alas, my master! What shall we do?” ¹⁶ He answered, “Don’t be afraid, for those who are with us are more than those who are with them.” ¹⁷ Elisha prayed, and said, “Yahweh, please open his eyes, that he may see.” Yahweh opened the young man’s eyes, and he saw; and behold, the mountain was full of horses and chariots of fire around Elisha.

¹⁸ When they came down to him, Elisha prayed to Yahweh, and said, “Please strike this people with blindness.” He struck them with blindness according to Elisha’s word. ¹⁹ Elisha said to them, “This is not the way, neither is this the city. Follow me, and I will bring you to the man whom you seek.” He led them to Samaria. ²⁰ When they had come into Samaria, Elisha said, “Yahweh, open these men’s eyes, that they may see.” Yahweh opened their eyes, and they saw; and behold, they were in the middle of Samaria. ²¹ The king of Israel said to Elisha, when he saw them, “My father, shall I strike them? Shall I strike them?” ²² He answered, “You shall not strike them. Would you strike those whom you have taken captive with your sword and with your bow? Set bread and water before them, that they may eat and drink, then go to their master.” ²³ He prepared a great feast for them. After they ate and drank, he sent them away and they went to their master. So the bands of Syria stopped raiding the land of Israel.