1 Samuel 20:16 - Ellicott's Commentary On The Whole Bible

So Jonathan made a covenant. — It is not necessary to supply (as in the English Version) “saying,” but it is better to understand this verse as a remark interposed in the dialogue by the narrator, and to translate the Hebrew literally, “So Jonathan made a covenant with the house of David, and Jehovah required it at the hand of David’s enemies.”