Here is the comment:

I remember watching one of the prominent Reformed teachers give a teaching series on the fruit of the Spirit, and he was promoting this exact same line of thought (that is, that we should assume the best of everyone), and he even acknowledged the difficulty of maintaining both this idea along with his beliefs about our fallen nature, but never provided resolution to the problem. He was teaching from 1 Corinthians 13 and went the route of “love believes all things” (or I think in some translations it is “love thinks no evil”), and the answer was essentially “we must always give the benefit of the doubt because God says so.” I suspect this is where a lot of this notion comes from, is (in part, but not exclusively) from a faulty understanding of the meaning/application of this passage that divorces it from the rest of Scripture (especially the book of Proverbs!). What would a more biblical way of understanding of that statement in 1 Corinthians 13 be? In particular, how do we reconcile the warnings of Proverbs and the epistles about bad people with 1 Corinthians 13?

Thinking this through, I shared these thoughts:

Well first of all teaching like that guy did certainly leaves the door wide open for the wicked to get away with most anything. We have to believe them you know – we have to assume their “repentance” is real, blah, blah, blah. But as you mentioned, the Bible is filled with texts that teach us NOT to believe everything people say. The fundamental reason we don’t believe them is because God doesn’t! God does not “think the best.” He does not “believe all things” in that sense. Jesus (John 8) told the Pharisees they were liars just like their father the devil. And John tells us (1 John 4) to test the spirits because many false prophets have gone out. So it is absolutely impossible that Paul means there in 1 Cor 13 that we are to always “think the best” and believe whatever people say.

So what does Paul mean?

1 Corinthians 13:7 ESV Love bears all things, believes all things, hopes all things, endures all things.

The issue here comes down to the definition of “all things.” The context (vss 1-6) show us what is meant. Paul means (read vss 1-6 again) that ALL THINGS we do – particularly all the things we do in Christ’s name – must be energized and driven by LOVE. If that is not the case, if our motive is anything else, then we are clanging symbols, I am nothing, a noisy obnoxious grating in God’s hearing and sight. We bear, we carry, share the load out of LOVE for the Lord and for others. Our faith, driven by love for Christ, believes all things He says. Our love impels us to confidently hope in all the promises Christ has made. And we endure all things for Christ, even if our body be burned as a result, because we LOVE Him. Without that motivation of love for Christ and others (first and second greatest commandments) everything we offer Him is NOTHING. That is why on that Day when He comes to judge all men, he will say to those on His left (who boast about all they have done in His name) to depart from Him, He never knew them.

Do you see how a superficial rendering of this passage such as that prominent preacher gave, absolutely guts the greatness of this scripture?

You must be born again.