2 Kings 6:11
Therefore the heart of the king of Syria was sore troubled for this thing; and he called his servants, and said unto them, Will ye not shew me which of us is for the king of Israel? Therefore the heart of the king of Syria was sore troubled for this thing; and he called his servants, and said unto them, Will ye not shew me which of us is for the king of Israel?
This took place while Elisha was revealing the Syrian king's plans and ambushes against Israel, so that they were repeatedly made known to Israel and frustrated. The Syrian king was deeply troubled by this repeated exposure of his plans and confronted his servants over it. He suspected that one of his own servants was secretly informing Israel and siding with the king of Israel. He did not understand that Elisha learned his plans from God.
When he learned that his ambushes had been frustrated, he sent an armed force to seize Elisha, but God delivered the prophet. After those Syrian soldiers were led to Samaria and sent back unharmed, Israel was free from Syrian attacks for a time, until Syria under another king later besieged Samaria again.