Jude concludes his case against his opponents by giving, in Jude 16, four reasons God will judge the false teachers.
(1) They resist God’s will and law.
They are “murmurers,” “grumblers.” The word is most often used of Israel in the wilderness and signifies the complaining and resistance to God’s will that characterized Israel in her time in the wilderness. This word connected to the “harsh things” or “hard sayings” in the previous verse.
Jude’s point is that the false teachers, like Israel in the wilderness, disputed the authority of God (Christ) and resisted his will, complaining about it, rather than accepting his will for them. No doubt the false teachers rejected the law as burdensome and useless.
The next word, translated “complainers” (KJV, NKJV), or “fault-finders” (NET) speaks to their discontent with God’s law and is closely connected to the previous word, serving to emphasize the severity of this sin.
2. They live according to their own desires rather than God’s.
The corollary to rejecting God’s will is to follow one’s own desires, which is what Jude lists next: “walking according to their own desires.”
Though the word translated “lusts” (KJV, NKV, NASB) is often used to refer to sexual desire, it can be understood in a neutral way in the sense of desires. It is probably best understood here not as a specific reference to sexual lust or to greed, but to one’s own desires as opposed to God’s desires.
Note the similarity to Isaiah 65:2, “I have stretched out My hands all day long to a rebellious people, Who walk in a way that is not good, According to their own thoughts.”
3. They are arrogant and presumptuous in their rejection of God’s law.
Jude’s description of their speech as “great swelling words” is not a general condemnation of arrogance in speech but an indictment against them for “their arrogant and presumptive attitude toward God, their insolent contempt for his commandments, their rejection of is moral authority which amounts to a proud claim to be their own moral authority” (Bauckham, 99).
4. They show favoritism in their teaching toward those who support them.
The final description is usually translated along the lines of “flattering people for the sake of gain” but the KJV and ESV get it correct when they translate “having men’s persons in admiration because of advantage” (KJV) or “showing favoritism to gain advantage” (ESV).
In the OT, the expression “to be a respecter of persons” was usually used in a judicial context and meant that one would show favoritism to someone, usually someone rich or powerful, for sake of a bribe or some other gift or favor shown in return.
Applied to teachers it means that they spoke what people wanted to hear (and still do today), especially those upon whom he depended. A good teacher in Jewish tradition was one who taught without showing partiality but instead truly taught the ways of God (Luke 20:21; cf. Matt. 22:16; Mark 12:14).
These teachers presented themselves as true teachers who spoke the word of God but instead of teaching and preaching God’s commands without partiality or fear, they set God’s commands aside so they would find acceptance among the people upon whom they depended for a living.
They speak big words against God to give their patrons an excuse for living without moral restraint. Contrast this with Paul’s statement about his ministry in Gal. 1:10: “for if I yet pleased men, I should not be the servant of Christ.” (KJV)