Charles Ellicott Commentary Hebrews 5:13

"For every one that partaketh of milk is without experience of the word of righteousness; for he is a babe." — Hebrews 5:13 (ASV)

The change of expression from having need of milk to partaking of milk (that is, making it the solo food) is significant. Those who are addressed had lost interest in the deeper truths of Christianity, those truths which alone expressed and explained its proper nature. Their temptation apparently was towards mingling a rudimentary Christian doctrine with the teaching of the synagogue. Yielding to this they would lose all real knowledge of the very elements of Christian truth, and with this all true knowledge of the Old Testament itself. The connection between this verse and the last may probably be, You have come to need milk, for—making it by choice your sole food—you stand self-confessed as babes.

Unskilful.—Rather, without experience. The word of righteousness evidently must signify complete, properly-developed Christian teaching. The only question is, why is this particular designation chosen? In the Epistle to the Romans such a description would be natural (Romans 9:31); but “righteousness” is not the direct and manifest subject of this Epistle. Still, the expressions which the writer uses in Hebrews 10:38; Hebrews 11:7, together with the general similarity between his teaching and Paul's, go very far towards explaining his choice of this special expression as descriptive of the religion of Christ. In like manner another phrase, law of liberty, is characteristic of James.