How do we relate in a helpful way with those who are (or are perceived to be) outside of orthodoxy? When you choose to interact with people with such views, there are certainly consequences to pay, but I propose there can be benefits to reap in the right circumstances.
Bad examples exist where evangelical Christians have been used by those outside orthodoxy to legitimize their aberrant views. In addition, the Scriptures warn us away from false teachers. Yet, I believe in interaction around the Scriptures in a way that leads to helpful conversations and theological clarity when such people are considering (or engaging in) moves toward orthodoxy.
Probably the most prominent example in modern times has to be the Worldwide Church of God. They were once a non-Trinitarian, heretical cult (their term, not mine), and are now an evangelical denomination and a member of the National Association of Evangelicals.
A couple of decades ago, I first learned that the Worldwide Church of God was on a theological journey, reconsidering some of its basic beliefs. Everyone had seen The Plain Truth magazine and knew of the teachings of both Herbert W. Armstrong and his son Garner Ted Armstrong. These teachings were largely considered (and rightfully so) to be heterodox. When I first met the local WCG leaders, they were a mix of views– some orthodox, some not, and still on a journey.
At that point, some would prefer to condemn them and demand they recant and renounce their friends before further conversation. I did not, and I am glad others did not.
Today, I have spoken at the Worldwide Church of God (now called Grace Communion International) annual meeting and consider their leadership to be friends. (I have blogged about them here). But the reason I could do that with only a little controversy was because some evangelical leaders chose to engage in relationship and conversation with those outside of orthodoxy in order to bring them to orthodoxy.