The matter of examining, judging and condemning those set-up by God to rule others dates back to the Old Testament. Moses, the man of God was judged and condemned by his closet relatives, Miriam and Aaron, while they were in the wilderness (Num. 12:1-2).
So also did Korah and his company to him (Num. 16:11-13). David, the king also shared of this evil phenomenon at the hand of Shimei, a descendant of king Saul (2Sam. 16:5-8), as well as prophet Ezekiel (Ezek. 33:30-33).
In the New Testament; John the Baptist did not escape it, neither did the Lord Jesus at the hand of religious but rebellious Jews (Matt. 11:18-19; Lk. 19:7; 6;6-7; Matt. 15:1-2; Jn. 5:10-13,18; 9:13-16,24).
The case of St. Paul, the one that is leading us into the study of this point is that of some Corinthians judging or criticizing his apostleship or ways.
Nonetheless, this phenomenon, whether toward ministers ro the flock is evil, and those engaged in it, either temporarily or permanently, are also evil. This is proved by the punishment and pronouncement made against such that engaged in the practice (cons. Num. 12:1-10; 16:1-3,25-33; Matt. 12:39; Lk. 11:29; Matt. 7:1-5).
One point is clear. Those usually engaged in this evil practice are as follows:- backslidden people, who themselves do not keep the word of God (eg. Ezek. 33:30; Matt. 15:1-9); people gripped by envy, like Korah and company (Num. 16:1-3); people who know not much, but think that they know too much (eg. Num. 16:1-3); people who have natural hypercritical minds, etc.