Religion . . . is the various communal, cultic means . . . by which human beings seek to know and to be happily related to the gods or God. In the sense in which I employ the word here, religion is a human enterprise. Thus, in Paul's view, religion is the polar opposite of God's apocalyptic act in Christ. . . . Religion, therefore, provides the human being 'with his most thorough-going possibility of confusing an illusion with God.'
This was what Paul came to see as he traveled to Damascus (Gal 1:13-14; Phil 3:6).
--J. Louis Martyn, Theological Issues in the Letters of Paul (T&T Clark, 1997), 79; quoting Ernst Kaesemann