OHC 258.3
(Our High Calling 258.3)
Your acquaintances who are utterly averse to spiritual things are not refined, ennobled, and elevated by the practice of the truth. They are not under the leadership of Christ, but under the black banner of the prince of darkness. To associate with those who neither fear nor love God, unless you associate with them for the purpose of winning them to Jesus, will be a detriment to your spirituality. If you cannot lift them up, their influence will tell upon you in corrupting and tainting your faith. It is right for you to treat them kindly; but not well for you to love and choose their society, for if you choose the atmosphere that surrounds their souls, you will forfeit the companionship of Jesus. By every means in your power seek to repress sin; but never for one moment give sanction to sin either by your deeds, your words, your silence, or your presence. Every time sin is sanctioned by the professed follower of Christ, his sense of sin is weakened, and his judgment thus becomes perverted.... (OHC 258.3) MC VC