Once in a while I come across people who decide there is no god because he "let them down."
It seems to me that they should decide what they do not believe, because if there is no God there is nobody to complain about. Nothing can be the fault of someone who does not exist.
In other words, you have to believe there is a God if you want to think that he has let you down. He may not be what you think he ought to be; but then, being God, he doesn't have to live up to your expectation of him. Being God, he gets to define himself.
I am one of those who agree with Jesus that there is a God, and he is good.
Jesus was not the first to say it. Hundreds of years before him the psalmist declared that God is good, because his steadfast love endures forever.
By "steadfast love," the psalmist meant love that keeps its word, love you can count on. The words of the marriage service, "I do promise and covenant," are about love that keeps its word. One person can keep a promise, but it takes two to keep a covenant: I make you a promise, but I offer you a covenant. When God says, "I love you," he means it forever, not just until he changes his mind. As he says in Jeremiah 31:3, I have loved you with an everlasting love; therefore I have continued my faithfulness to you.
When we say that God is good, we mean that everything God should be, he is; everything God should do, he does. When we call each other good, we do not mean that we do all we should do, or are everything we should be. Our goodness is not in our essential nature, as it is in God's. We are not God; we are no more than the image of God.
We cannot be good in ourselves, but we may at least will the good. Purity of heart is to will one thing, said the Danish philosopher Kierkegaard more that 150 years ago. "The good" is the one thing.
Jesus said that God alone is good because only God merges perfectly and seamlessly who he is with what he does and says. Creatures of flesh are unable to do that, but our wills can say yet to it. We may not attain to it, but we may believe it.