We ought not to withdraw entirely from all communion with unconverted people. It would be cowardice and indolence to do so, even if it were possible. It would shut us out from many opportunities of doing good. But we ought to go into their society moderately, watchfully, and prayerfully, and with a firm resolution to carry our Master and our Master’s business with us.

~ J.C. Ryle

Expository Thoughts on the Gospels: Luke volume 2 , [Carlisle, PA: Banner of Truth, 1998], 147.