Not Because You Must
A word of wisdom from Douglas Frank in Randall Balmer's book on Evangelicals, "Mine Eyes Have Seen the Glory":
"The gospel says we're all bastards, but God loves us anyway. The moralist says, 'Maybe you're a bastard and I used to be one.' That's a betrayal of the gospel, the good news of our salvation through Christ. The bible teaches that Jesus saves us in spite of ourselves."
And, prompted by Scot McKnight, an invitation to communion from the Covenant Book of Worship:
“Come to this sacred table, not because you must, but because you may; come not to testify that you are righteous, but that you sincerely love the Lord Jesus Christ and desire to be his true disciples; come not because you are strong but because you are weak; not because you have any claim on the grace of Christ but because of your frailty and sin you stand in constant need of his mercy and help; come not to express an opinion, but to seek his presence and pray for his Spirit.”