Jude

22 Be merciful to those who doubt; 23 save others by snatching them from the fire; to others show mercy, mixed with fear—hating even the clothing stained by corrupted flesh.
For us to hate even the clothing stained by corrupt flesh means that we're to hate the sin but we must also love the sinner and be a witness of Christ to them. Basically this is when we reach out to others, but continuously checking ourselves against scripture.