Why did God show us His authority, let us see His mercy complimented by His justice, and reveal His faithfulness and goodness to us? Because God wanted us to discover He is a God of love.
We want to know that God is good before we trust in Him. But in order for God to display He is good, we have to sometimes go through an undesirable circumstance.
We wrestle with doing what we like over what's right. This was something that humanity has wrestled with since the beginning. A problem is created when we pick what we like over what's right that creates the reason Jesus comes to show us God's justice against evil and His mercy toward those who trust in Him.
When we look at the origin story of the Israelites through the lens of the exodus we see that God delivered them to discover Him. We also can see our story too and we can begin to discover God.