Saint Augustine differentiates between two kinds of doctrinal error:
Unintended inaccuracy that the Bible teacher shares in his earnest effort to promote love for God and neighbor. It has no malicious intent.
Intentional deception that the Bible teacher designs to take advantage of believers, to drive them away from obedience to Christ or to sow discord among them.
Saint Augustine differentiates between mistaken teachers (type 1) and malicious deceivers (type 2). I would add to that lesson that it is wrong for one to assume himself immune from unwittingly teaching errors (type 1), all the more so if he condemns as type 2 deceivers those who are just trying to bless people with their Bible studies while making unwitting mistakes, (type 1). Jesus said, "You will know them by their fruits," LINK. (Note: Jesus did not say, "You will know them by their creeds" or "by their super-apostle commentaries" or "by their denominational sign" or "by their theological jargon, extra-biblical vocabulary" or "by their name-dropping of famous Christians" or "by their friends," etc.).
From: Saint Augustine's City of God and Christian Doctrine, pages 845-847
Chapter 36.—That Interpretation of Scripture Which Builds Us Up in Love is Not Perniciously Deceptive Nor Mendacious, Even Though It Be Faulty. The Interpreter, However, Should Be Corrected.
40. Whoever, then, thinks that he understands the Holy Scriptures, or any part of them, but puts such an interpretation upon them as does not tend to build up this twofold love of God and our neighbor, does not yet understand them as he ought. If, on the other hand, a man draws a meaning from them that may be used for the building up of love, even though he does not happen upon the precise meaning which the author whom he reads intended to express in that place, his error is not pernicious, and he is wholly clear from the charge of deception. For there is involved in deception the intention to say what is false; and we find plenty of people who intend to deceive, but nobody who wishes to be deceived. Since, then, the man who knows practises deceit, and the ignorant man is practised upon, it is quite clear that in any particular case the man who is deceived is a better man than he who deceives, seeing that it is better to suffer than to commit injustice. Now every man who lies commits an injustice; and if any man thinks that a lie is ever useful, he must think that injustice is sometimes useful. For no liar keeps faith in the matter about which he lies. He wishes, of course, that the man to whom he lies should place confidence in him; and yet he betrays his confidence by lying to him. Now every man who breaks faith is unjust. Either, then, injustice is sometimes useful (which is impossible), or a lie is never useful.41. Whoever takes another meaning out of Scripture than the writer intended, goes astray, but not through any falsehood in Scripture. Nevertheless, as I was going to say, if his mistaken interpretation tends to build up love, which is the end of the commandment, he goes astray in much the same way as a man who by mistake quits the high road, but yet reaches through the fields the same place to which the road leads. He is to be corrected, however, and to be shown how much better it is not to quit the straight road, lest, if he get into a habit of going astray, he may sometimes take cross roads, or even go in the wrong direction altogether.
Chapter 37.—Dangers of Mistaken Interpretation.
For if he takes up rashly a meaning which the author whom he is reading did not intend, he often falls in with other statements which he cannot harmonize with this meaning. And if he admits that these statements are true and certain, then it follows that the meaning he had put upon the former passage cannot be the true one: and so it comes to pass, one can hardly tell how, that, out of love for his own opinion, he begins to feel more angry with Scripture than he is with himself. And if he should once permit that evil to creep in, it will utterly destroy him. “For we walk by faith, not by sight, 2 Cor 5:7. Now faith will totter if the authority of Scripture begin to shake. And then, if faith totter, love itself will grow cold. For if a man has fallen from faith, he must necessarily also fall from love; for he cannot love what he does not believe to exist. But if he both believes and loves, then through good works, and through diligent attention to the precepts of morality, he comes to hope also that he shall attain the object of his love. And so these are the three things to which all knowledge and all prophecy are subservient: faith, hope, love.