Receive, I pray thee, the law from his mouth; or, receive now instruction from his mouth. The supposition of some commentators, that the "Law of Moses" is intended, is negatived by the entire absence from the Book of any allusion to the details of the Mosaic legislation, as well as by the primitive character of the life depicted in the book, and the certainty that no one of the interlocutors is an Israelite.
The Hebrew תּוֹרה, without the article prefixed, is properly "instruction," and is only to be assumed as meaning "the Law" when the context shows this meaning to be probable. The "instruction" to which Eliphaz here points, and which he regards as instruction from God's mouth, is probably the teaching of religious men, such as himself, which he considered to have come from God originally, though, perhaps, he could not have explained how.
And lay up his words in thine heart. This is a mere variant of the preceding clause, and adds no fresh idea.