In his letter to the church at Colossae, Paul is at great pains to emphasize the importance of not being burdened in our faith by expectations and demands that fall outside the bounds of the gospel message. It’s important that the “good news” not become “bad news” for us by accepting the fetters of “do not touch” or “do not eat” injunctions and proscriptions.
This gets into the territory of knowing what “sound doctrine” is… and of being able to discern when some theological charlatan is interested in “leading us astray,” as it were.
Sadly, this vigilance often also leads us into all sorts of other things that are simply not our business: judging who is “on our side” and who is not, and imagining that we can understand the motive and spirit behind those with whom we disagree… much less understanding how God is moving and breathing in all His children.
Let’s just accept for a moment the notion that we are mature enough and discerning enough to actually identify some doctrinally-suspect person as an agent of the enemy. What then? Does that grant us license for hate, for exclusion, for finger-pointing and bile? For snide or smug comments that clearly delineate us as enlightened and “saved” while calling out the other as a poor deluded schmuck or worse, a heretic?
Hardly. Such a one becomes cause for prayer, and love… if, in fact, we have our own doctrine straight. After all, while we were yet enemies, Christ died for us… if we are believers, and actually believe what we claim to believe.
Having my doctrine straight only benefits me. It has no bearing at all on someone else’s relationship with God. It’s up to the Spirit to bring others—step by step, sometimes two forward and one back, and sometimes circuitously—to God, as the Spirit sees fit. My job is be true to what God has shown me, and to love and show mercy and compassion as I go—being at peace, as far as it depends on me, with all.
It is far better to discern God’s Spirit in others, even in some small, barely-germinating way, than to be hypervigilant about ferreting out a spirit of malice.