But we also fail to treat God as God by questioning His wisdom and goodness when our circumstances don’t go the way we want them to go. When we grumble and complain about having our wallets stolen, our reputations maligned, or our lives turned upside down by some other kind of hardship, we are saying that we know better than God does. We are saying that something is wrong with His providential care of the world or, worse, that something is wrong with Him—namely, that He must not be all-wise or all-loving or altogether good. Ingratitude in adverse circumstances is therefore just as prideful as the ingratitude we display in the best of circumstances. In both cases, we are refusing to give God the glory that He alone is due or, in the words of Romans 1:21, we are not honoring God as God.
The point in all this is simply to say that when we are ungrateful, we are acting like non-Christians. We are acting as though God did not exist. Ingratitude is not a sin that we should wink at or be unconcerned about. It strikes at the very core of the Christian faith, because it treats God as though He were not God. And what is more, ingratitude cheapens grace. It overlooks the cost of the gift of salvation that we have been given and diminishes the value of that gift by ascribing greater value to something else that God, in His providence, has chosen not to give us. That may be the real and lasting tragedy of ingratitude. It devalues the person and work of Jesus Christ, who really is the Pearl of Great Price (Matt. 13:46) and the Fairest among ten thousand (Song 5:10).