If John the apostle emphasized Jesus's eternal relationship with God in John 1:1-2, he did more so with Jesus's involvement in creation in verse 3. Jesus had a huge part in the creation of the world. Even in Genesis 1, we can see a hint of His presence in the creation of the universe. Here, the author of this Gospel makes Jesus's presence clear.
Notice that John the apostle states Jesus's role in creation in two ways. First, he makes it clear that everything in creation was created through Him. Then, the apostle takes the negative and makes it clear that without Jesus, nothing was created. John the apostle intended for this to be emphasized. Jesus was present at creation, and it was through Him that God created everything.
If God created everything through Jesus, then everything we have is His anyway. It is very easy for us to get caught up in the idea that something is ours without realizing that, if not for God's creative work through Jesus, we would not have anything. In fact, we would not even exist! Since we owe everything to God, we have no reason not to humble ourselves before Him.