Jerome : Verse 4. "'I beseech Thee, O Lord God, who art mighty and terrible...'" That is, Thou art terrible towards those who despise Thine injunctions. "'...Who keepest covenant and mercy towards those who love Thee and keep Thy commandments.'" It is not therefore the case that what God promises will come to pass without further ado, but rather, He fulfils His promises towards those who keep His commandments. — St. Jerome, Commentary on Daniel, CHAPTER NINE Theodoret of Cyrus : [Daniel] calls [God] "great and wonderful" for his ability to do great and wonderful things. Godly people, after all, are accustomed to apply divine names on the basis of benefits conferred. He spoke of his "keeping covenant and mercy with those who love him" in recalling the promises to Abraham, Isaac and Jacob. Being very precise in his prayer, he mentions that he does not keep it with anyone but with "those who love him and keep his commandments;" if someone transgresses your commands, he renders himself unworthy of the promises. — COMMENTARY ON Daniel 9:4