7:1 "judge not" - and yet in 7:6 we are told to judge. Paul
enjoins the Corinthians not to judge the "motive of men's hearts"
1 Corinthians 4:5.
A few paragraphs later he rebukes them for having not "removed from
your fellowship the man who did this"
1 Corinthians 5:2.
God tells Samuel that "man sees the outward appearance". We can
judge the fruit, but not the heart. Luke records Jesus as saying
"condemn not" Luke 6:37, and
here in Matthew, "krino" means to render final judgement in a court -
something we cannot do when it come to a final judgement. But again, Paul
enjoins the Corinthians to judge disputes among believers within the church
1 Corinthians 6:2-4.
And Jesus in 7:16 says to judge others by their fruit.
In the Catholic world, "Christian" is defined externally - are you
properly baptized? In the Protestant world, "Christian" is defined
subjectively - are you a real believer? This latter definition can lead
to saying "he is not a real believer", rather than judging actions.
When we judge the worth of a person based on externals,
"we are become judges with evil motives"