Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. (Rom.1:21) KJV For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts. (Rom 1:21) ESV With such an idea of God, nothing which they may attempt to offer in the way of worship or obedience can have any value in his sight, because it is not him they worship, but, instead of him, the dream and figment of their own heart. This corrupt procedure is admirably described by Paul, when he says, that “thinking to be wise, they became fools” (Rom. 1:22). He had previously said that “they became vain in their imaginations,” but lest any should suppose them blameless, he afterwards adds that they were deservedly blinded, because, not contented with sober inquiry, because, arrogating to themselves more than they have any title to do, they of their own accord court darkness, nay, bewitch themselves with perverse, empty show. Hence it is that their folly, the result not only of vain curiosity, but of licentious desire and overweening confidence in the pursuit of forbidden knowledge, cannot be excused.

~ John Calvin Institutes

The Chestnut Mare