Jude 1:16

“These are murmurers, grumblers, etc. The more anyone murmurs and grumbles about the present labors of the Church, the less they have extinguished the desires of the flesh within themselves. But on the contrary, holy Daniel and other men of heavenly desires, as diligently as they only desire the things above, so much more scornfully do they despise all passing things that seem adverse.”

“After this, having left off the comparison of the ungodly, he now proceeds to the actual exposure of them, calling them murmurers and fault-finders. A murmurer is one who through clenched teeth and timidly censures what is displeasing to him, while a fault-finder is one who always and at everything laughs. These vile ones are murmurers and fault-finders. They are murmurers, for they do not dare openly to make use of their teaching, on account of its vileness, since it is unsafe to publicize their ungodliness, which is joined with debauchery and blasphemy. They are fault-finders, because they slander everything that belongs to others and truth itself, in order to more firmly establish their own evil and debauchery. What was said above, that the heretics, like Balaam, were carried away by reward, he now explains with the words: they "show partiality" for the sake of "gain." To show partiality means to deal flatteringly with those in authority.”

“These are grumblers, complainers, walking according to their own lusts; and their mouth speaks great swelling words, flattering people to gain advantage. After this, however, having been freed from the accommodation of these ungodly ones, Jude now also addresses the matter itself, accusing their vices, calling them grumblers and complainers. There is indeed a grumbler, one who, under his breath and without speaking out, complains to the one who is displeased. The complainer, on the other hand, always and constantly engages in contempt. These wretched ones are murmurers and complainers, Jude says. For they do not have the boldness to engage in their teaching through shameful means. For it is not without danger to publicly proclaim recklessness with wickedness and blasphemy. And they are complainers, slandering both other people and the truth, in order to set up their own evils and obscenity as if they were something good. As he has said concerning Balaam, that they have poured themselves out for profit just like him, he now states more clearly that they flattering people to gain advantage, admiring indeed, by flattering those in authority, but the profit is actually the gain.”