14 You are the God who performs miracles; you display your power among the peoples.
15 With your mighty arm you redeemed your people, the descendants of Jacob and Joseph. Psalm 77:14-15
God clearly displayed his mighty power when He redeemed Israel, which is what Asaph was referring to. He didn’t have to, and He didn’t need to but He did it anyhow.
I too am amazed at what Christ has done on our behalf. Why? Why, I ask. I mean, who are we? In the entire universe with all its complexities and vastness, who are we that He would give us even a thought? Not only who are we but why? Well, the why is simple: it’s totally in God’s character to care about us. It really has nothing to do with us or what we can do to earn his favor.
And yet in the grandest of paradoxes, it had everything to do with us, not that we deserved it or even wanted it. It’s all for His glory.