Although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened. (Romans 1:21)
When gratitude springs up in the human heart toward God, he is magnified as the wealthy source of our blessing. He is acknowledged as giver and benefactor and therefore as glorious.
But when gratitude does not spring up in our hearts at God's great goodness to us, it probably means that we don't want to pay him a compliment; we don't want to magnify him as our benefactor.
And there is a very good reason that human beings by nature do not want to magnify God with thanksgiving or glorify him as their benefactor. The reason is that it detracts from their own glory, and all people by nature love their own glory more than the glory of God.
At the root of all ingratitude is the love of one's own greatness. For genuine gratitude admits that we are beneficiaries of an unearned bequest. We are cripples leaning on the cross-shaped crutch of Jesus Christ. We are paralytics living minute by minute in the iron lung of God's mercy. We are children asleep in heaven’s stroller.
Natural man hates to think of himself in these images: unworthy beneficiary, cripple, paralytic, child. They rob him of all his glory by giving it all to God.
Therefore, while a man loves his own glory, and prizes his self-sufficiency, and hates to think of himself as sin-sick and helpless, he will never feel any genuine gratitude to the true God and so will never magnify God, but only himself.
“Those who are well have no need of a physician, but those who are sick. I came not to call the righteous, but sinners” (Mark 2:17).
Jesus has nothing to do for those who insist they are well. He demands something great: that we admit we are not great. This is bad news to the arrogant, but words of honey to those who have given up their charade of self-sufficiency and are seeking God.