Acts 20:21

Testifying both to Jews and . . . Greeks--laboring under a common malady, and recoverable only by a common treatment. repentance toward God, and faith toward our Lord Jesus Christ--(See on Act 5:31). REPENTANCE, as distinguished from faith, is that state of the "honest and good heart" which arises from a discovery of one's contrariety to the righteous demands of the divine law. This is said to be "toward God," because seeing Him to be the party dishonored by sin, it feels all its acknowledgments and compunctions to be properly due to Him, as the great Lawgiver, and directs them to Him accordingly; condemning, humbling itself, and grieving before Him, looking also to Him as its only Hope of deliverance. FAITH is said to be "toward our Lord Jesus Christ," because in that frame of mind just described it eagerly credits the testimony of relief divinely provided in Christ, gladly embraces the overtures of reconciliation in Him, and directs all its expectations of salvation, from its first stage to its last, to Him as the one appointed Medium of all grace from God to a sinful world. Thus we have here a brief summary of all Gospel preaching. And it is easy to see why repentance is here put before faith; for the former must of necessity precede the latter. There is a repentance subsequent to faith, the fruit of felt pardon and restoration.

— Jamieson-Fausset-Brown Commentary (public domain)