Sin is corruptive. It destroys us at our very core. But no where does sin show us “its full range and possibility” than in religion.
In his book Not The Way It’s Supposed To Be, Cornelius Plantiga Jr. quotes Geoffrey W. Bromiley:
The inward corruption to which Jesus refers in the scathing denunciation in Matthew 23 is not the corruption of deliberate and calculated insincerity. It is the corruption of a sincere and sincerely practiced religion, which is ultimately a supreme manifestation of religious pride…. The frightening picture opened up here is that when one recognizes obvious sin one has hardly begun to reckon seriously with this adversary. The open and blatant sinner, the oppressor or the harlot, is indeed a sinner. But it is not here that the genuine depth of sin is revealed, not even if the oppressor be ever so grasping or the harlot ever so shameless. It is in religious persons that the depths are to be seen.
So we ask ourselves, as did the Apostle Paul, “Who will deliver me from this body of death?” And to which the answer is: Thanks be to God through Jesus Christ our Lord! (Romans 7:24-25)
That is a really good book to read!