LEV459 If you observe someone who either says something or performs a particular deed, and his words or actions can be judged in either a negative or positive way -- if he is a God-fearing individual, you must judge him favorably, by way of the truth (I.e., even though the circumstantial evidence points toward guilt, since he is God-fearing, in truth he is probably innocent), even if the facts are closer and lean more toward his guilt. If he is within the norm, people who [on the whole] are careful not to sin, and yet sometimes falter, you must give him the benefit of the doubt and judge him favorably (Here Rabbeinu Yonah does not add, "by way of the truth."), as our Sages, z"l, said (Shabbos 127b), "Whoever judges his fellow man favorably, will [himself] be judged favorably by the Omnipresent." This is a positive commandment of the Torah, as the pasuk says [this verse], "You shall judge your fellowman justly." If the facts lean toward his guilt, you must treat it as you would any uncertainty – – do not tip the scales against him. But if the majority of his deeds are [geared] towards evil, or if you have checked that within his heart there is no fear of God, then [you must allow] his words and deeds [to] tip the scales against him, as the pasuk says (Mishlei 21;12), "A righteous person understands the house of the wicked; he construes the wicked towards evil." We have already explained this (Rabbeinu Yonah elaborates upon this verse in his commentaries to Mishlei (21:12) and Avos (1:6).