It puts the best possible motives behind the conduct of others, and is not suspicious without good cause. Then let's give others the benefit of the doubt. Christ is saying here that it is the hypocrite who tries to be honest about others, without first being honest with and about themselves. They judge others according to the word of God without first judging themselves according to the word of God. They are quick to point out the faults of others from God's word, but if anyone tries to say anything to them, they are unbelieving and maybe even hostile.
Human nature looks at everyone in the worse possible light.
If they do a good work, we say that their motives are impure, or they are doing it for themselves, or that they are working against us. Paul points out here that love desires to think the best of others, therefore will not connect evil or improper motives with the actions of others. Christian love views that individual in the best possible light until confronted with cold hard facts otherwise. Of course the unsaved rejoice when a Christian goes wrong, but this is not addressed to the unsaved. First, the Child of God doesn't gloat over other's wickedness or when the results of sin catches up with them .