Wishing to be teachers of the law He does not reprove those who openly attack the instruction of the law, but those who boast of belonging to the rank of teachers of it. He affirms that such persons have no understanding, because they harass their faculties to no purpose by curious questions. And, at the same time, he rebukes their pride by adding, -- Of what things they affirm, for none will be found more bold in pronouncing rashly on matters unknown to them than the teachers of such fables. We see in the present day with what pride and haughtiness the schools of the Sorbonne pronounce their authoritative decisions. And on what subjects? On those which are altogether hidden from the minds of men -- which no word of Scripture, and no revelation has ever made known to us. With greater boldness do they affirm their purgatory [1] than the resurrection of the dead. As to their contrivances about the intercession of the saints, if we do not hold them to be an undoubted oracle, they cry out that the whole of religion is overturned. What shall I say as to their vast labyrinths about the hierarchies of heaven, relationships, and similar contrivances? It is a matter that has no end. The Apostle declares that in all these is fulfilled what is said in a well-known ancient proverb, "Ignorance is rash;" as he says that, "puffed up by their carnal mind, they intrude into things which they know not." (Colossians 2:18.)

Footnotes

1 - "And in Popery what are the articles that shall be held as most certain? What angel, or what devil, revealed to them that there is a purgatory? They have fabricated it out of their own brain, and, after having attempted to produce some passages of the Holy Scriptures, they have at length become bewildered, so that they have no defense of their purgatory, but its antiquity. There it is! It has been always held.' Such is the foundation of faith, according to the learned Papists. And then we must not call in question that we ought to apply to the departed saints as our advocates and intercessors. To go to God without baying as our guide St. Michael, or the Virgin Mary, or some other saint whom the Pope shall have inserted in his calendar for the occasion, would be of no avail. And why? On what ground? Will they find in all the Holy Scriptures a single word, a single syllable, to shew that creatures, that is, deceased persons, intercede for us? For in this world we ought to pray for one another, and that is a mutual obligation; but as to deceased persons, not a word is said about them." -- Fr. Ser.

Desiring to be teachers of the law - That is, to have the credit and reputation of being well versed in the law of Moses, and qualified to explain it to others. This was a high honor among the Jews, and these teachers laid claim to the same distinction.
Understanding neither what they say - That is, they do not understand the true nature and design of that law which they attempt to explain to others. This was true of the Jewish teachers, and equally so of those in the church at Ephesus, who attempted to explain it. They appear to have explained the law on the principles which commonly prevailed among the Jews, and hence their instructions tended greatly to corrupt the faith of the gospel. They made affirmations of what they knew nothing of, and though they made confident observations, yet they often pertained to things about which they had no knowledge. One needs only a slight acquaintance with the manner of teaching among Jewish rabbies, or with the things found in their traditions, to see the accuracy of this statement of the apostle. A sufficient illustration of this may be found in Allen's "Modern Judaism."

Teachers of the law - To be esteemed or celebrated as rabbins; to be reputed cunning in solving knotty questions and enigmas, which answered no end to true religion. Of such the rabbinical teaching was full.
Understanding neither what they say - This is evident from almost all the Jewish comments which yet remain. Things are asserted which are either false or dubious; words, the import of which they did not understand, were brought to illustrate them: so that it may be said, They understand not what they say, nor whereof they affirm. I will give one instance from the Jerusalem Targum, on Genesis 1:15 : And God made two great lights, and they were equal in splendor twenty-one years, the six hundred and seventy-second part of an hour excepted: and afterwards the moon brought a false accusation against the sun, and therefore she was lessened; and God made the sun the greater light to superintend the day, etc. I could produce a thousand of a similar complexion.

(6) Desiring to be teachers of the law; understanding neither what they say, nor whereof they affirm.
(6) There are none more unlearned, and more impudent in usurping the name of holiness, than foolish babblers, who reason fallaciously.

Desiring to be teachers of the law,.... They were very fond of being called Rabbi, Rabbi, and styled doctors of the law, and of being thought to have skill in interpreting the law, and good talents in expounding it, and preaching upon it; which was now most in vogue, and gained the greatest applause, when the preaching of the Gospel was treated with contempt, not only by the unbelieving Jews, but by judaizing Christians, and carnal professors,
Understanding neither what they say, nor whereof they affirm: they did not understand the law, the nature and end, the purity and spirituality, and perfection of it, which they were so fond of teaching, and went into many foolish and unlearned questions about it; see 2-Timothy 2:23, and which they as foolishly answered: these are the ignorant and unlearned men, who, notwithstanding their vain show of learning, and pretence to skill in interpreting the law, wrested the Scriptures to their own destruction, and that of others; they were ignorant of the things they talked of, and knew not by what arguments to confirm them, and yet were very bold and confident in their assertions: and generally speaking so it is, that those who can prove least assert most, and that with the greatest assurance.

Sample of their "vain talk" (1-Timothy 1:6).
Desiring--They are would-be teachers, not really so.
the law--the Jewish law (Titus 1:14; Titus 3:9). The Judaizers here meant seem to be distinct from those impugned in the Epistles to the Galatians and Romans, who made the works of the law necessary to justification in opposition to Gospel grace. The Judaizers here meant corrupted the law with "fables," which they pretended to found on it, subversive of morals as well as of truth. Their error was not in maintaining the obligation of the law, but in abusing it by fabulous and immoral interpretations of, and additions to, it.
neither what they say, nor whereof--neither understanding their own assertions, nor the object itself about which they make them. They understand as little about the one as the other [ALFORD].

Understanding neither the very things they speak, nor the subject they speak of.