James 4
11 Speak not evil one of another, brethren. He that speaketh evil of his brother, and judgeth his brother, speaketh evil of the law, and judgeth the law: but if thou judge the law, thou art not a doer of the law, but a judge.
12 There is one lawgiver, who is able to save and to destroy: who art thou that judgest another?
I absolutely agree with you that this is a tricky passage. As with every passage, I believe context reveals vital information. In the case of James, I think that we must look not only at the surrounding verses, but at other key verses.
James makes the statement "He that speaketh evil of his brother, and judgeth his brother, speaketh evil of the law, and judgeth the law:" So here he is equating these two things. In other words, that by speaking evil of and judging a brother, that person is speaking evil of the law and judging the law. I will come back to that.
James then goes on to explain that when somebody judges the law, then they are no longer "a doer of the law", but a judge.
Now that phrase "a doer of the law" should spark a memory. James said something similar in the first chapter verse 22. "be ye doers of the word, and not hearers only, deceiving your own selves." Okay, "doer of the law" and "doers of the word". Let's look at the context of verse 22. Start in verse 19.
James 1
19 Wherefore, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath:
20 For the wrath of man worketh not the righteousness of God.
21 Wherefore lay apart all filthiness and superfluity of naughtiness, and receive with meekness the engrafted word, which is able to save your souls.
22 But be ye doers of the word, and not hearers only, deceiving your own selves.
When a person speaks evil of his Brother, I submit that he is contradicting verse 19 & 20. Why would a person speak evil of his Brother? To get even, to punish, to exact their own wrath and vengeance. Vengeance is mine saith the Lord. As James says, a man's wrath does not work God's righteousness. When a person speaks evil of their brother, they are exacting
their wrath which does not work God's righteousness, so there is no way the judgment associated with the evil speaking can be righteous. They are setting themselves up as an authority over their brother, to punish them, to exact their wrath. We are allowed to judge righteous judgment, and we are allowed to withdraw fellowship, but we are not allowed to punish, to avenge. God has reserved that authority for himself. Those who take that authority unto themselves, have usurped God's authority.
If a person speaks evil of the law, then they have set themselves up as an authority above the law, judging for themselves that the law is not right. They judge the law, determining that it is not right, so they do not obey the law, they are not a doer of the law, but rather a judge. They have usurped the authority of God, because there is only one lawgiver. This passage would also speak against those who would corrupt, add to, and take away from the word of God. But that's another post, I won't say any more here.
Now back to speaking evil of a brother being akin to speaking evil of the law. When a person judges the law, they are putting themselves in God's place, which they have no right to do. When they speak evil of a fellow Christian, they are doing so in order to exact their own wrath against that person, they are putting themselves in God's place, which they have no right to do. Man's wrath does not work the righteousness of God.
And now we are back to when a person speaks evil of another Christian and then judges that person, the judgment will be tainted, it will not be righteous, and it will be for an ulterior motive.
This is a much harder passage to understand, and even harder to try and explain. I pray my attempt is true to the passage and that it is understandable. This is how I understand it and reconcile it with the other passages.
This was a difficult and challenging passage, Thank you!
I've been checking to see if someone else would post a better response so that all I had to do was say "Ya, what he said!!"