"in order that in the coming ages he might show the incomparable riches of his grace, expressed in his kindness to us in Christ Jesus."
Why?!? Why has he seated us with him in the heavenly realms. Why has he made us alive, who were once dead? Why has he freed us from the ruler of this world? Why?!?
It is to show his glory. He wanted to demonstrate the "incomparable riches of his grace." He wanted it to be known that he is over all and above all. And he wanted to demonstrate that through Christ Jesus.
We are all so far from his grace, and so undeserving. When we are honest with ourselves, we know that we are truly despicable, wretched people. But God, who is rich in mercy... He is the one who has decided to save the unsavable, to love the unlovable, to mend the unmendable, to make alive those who are dead.
What a God we serve.