Usually the dog that barks the loudest is not the most dangerous. Sometimes, a barking dog will only bark and never bite. This is what we see happening in Isaiah 37 with the nation of Assyrian.
The Assyrians have come up against Jerusalem. They have been steadily taking over nation after nation. They arrogantly assume they will do the same to Jerusalem.
But when Hezekiah and the people of the city turn to God, He delivers them in one night. After much boasting and bragging about what they have done and will do, the last three verses of Isaiah 37 record their destruction.
The Angel of the Lord goes out and in one night kills 185,000 of their warriors. The king goes home and a few years later is assassinated by his sons! None of their threats come to pass.
This teaches us that the enemies of the Lord are no match for His power. They may ‘bark’ and want to make us afraid, but we cant trust in the Lord (v.6-7). We should spread their threats and lies before the Lord like Hezekiah did (v.14). And we should not be afraid or intimidated.