Of the foolish - The word “foolish” is used in the Scriptures in two significations: to denote those who are void of understanding, and to denote the wicked. Here it is clearly used in the former sense, signifying that the Jew esteemed himself qualified to instruct those without knowledge.
Of babes - This is the literal meaning of the original word. The expression is figurative, and denotes those who were as ignorant as children - an expression which they would be likely to apply to all the Gentiles. It is evident that the character bare given by Paul to the Jews is one which they claimed, and of which they were proud. They are often mentioned as arrogating this prerogative to themselves, of being qualified to be guides and teachers of others; Matthew 15:14; Matthew 23:2, Matthew 23:16, Matthew 23:24. It will be remembered, also, that the Jews considered themselves to be qualified to teach all the world, and hence evinced great zeal to make proselytes. And it is not improbable (Tholuck) that their Rabbies were accustomed to give the names “foolish” and “babes” to the ignorant proselytes which they had made from the pagan.
Which hast the form of knowledge - The word translated here as “form” properly denotes a delineations or picturing of a thing. It is commonly used to denote also the appearance of any object; what we see, without reference to its internal character; the external figure. It sometimes denotes the external appearance as distinguished from what is internal; or a hypocritical profession of religion without its reality; 2 Timothy 3:5. “Having the form of godliness, but denying its power.” It is sometimes used in a good, and sometimes in a bad sense. Here it denotes that in their teaching they retained the semblance, sketch, or outline of the true doctrines of the Old Testament. They had in the Scriptures a correct delineation of the truth. Truth is the representation of things as they are; and the doctrines which the Jews had in the Old Testament were a correct representation or delineation of the objects of knowledge; compare 2 Timothy 1:13.
In the law - In the Scriptures of the Old Testament. In these verses the apostle concedes to the Jews all that they would claim. Having made this concession of their superior knowledge, he is prepared with the more fidelity and force to convict them of their deep and dreadful depravity in sinning against the superior light and privileges which God had conferred on them.