Albert Barnes Commentary 1 Timothy 1:7

"desiring to be teachers of the law, though they understand neither what they say, nor whereof they confidently affirm." — 1 Timothy 1:7 (ASV)

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 therefore their instructions tended greatly to corrupt the faith of the gospel. They made affirmations about things they knew nothing about; and though they made confident asseverations, these often concerned matters about which they had no knowledge.

One needs only a slight acquaintance with the manner of teaching among Jewish Rabbis, 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."