Russell Wilson & Ciara -- No Sex Before Marriage ... 'Pray for Us'

Russell Wilson is literally practicing what he preaches ... saying that he and his super fine pop superstar GF Ciara aren't doing the horizontal bedroom dance until after their wedding dance.

Wilson sat down for an Q&A session at The Rock church yesterday where he talked about his relationship with Ciara and dropped a holy bombshell about their sex life.

"I asked her what would you do if we took all that other stuff off the table and did it Jesus' way, no sex?"

Russell says Ciara agreed ... and since that time, their hot and heavy relationship has been filled with cold showers ... and absolutely NO banging.

Wilson does admit staying celibate ain't easy since Ciara is a "15 out of 10" ... so he's begging the churchgoers and Christians all around to help him in his journey.