Well, we see throughout the Book of Isaiah that it is that God has spoken to the people of Israel. God has revealed Himself to them, and He has caused them to hear. He is doing this, and so they know who He is. Later on, down in this passage, after this acknowledgment of this God who did all this creating work, the God who made everything. Remember, as we've been seeing, as we've been through the Ten Commandments, there's this important idea between the gods of the nations and the God of Israel. The God of Israel is other. He is separate from the creation. He is not like the creation. There is a creator creation distinction, important to understand. They don't have this with the pagan gods that they go running after. And here we see that the real difference is that God speaks and He causes His people to listen. We see this in verse 19. I did not speak in secret in a land of darkness. I did not say to the offspring of Jacob, 'Seek me in vain. ' He didn't say, Hey, come find me if you can. God spoke with a purpose to His people.