The way the Greek is put together indicates that John is thinking here of the faith that has its source in Jesus. In other words, this is the faith that Jesus taught and the faith that Jesus illustrated through his own life (literally, “the faith of Jesus”). He taught that the kingdom of heaven was near (Matthew 4:17; Matthew 10:7), then went to the cross to inaugurate the kingdom (Luke 22:16, Luke 22:18). Particularly on the cross Jesus suffered satanic attack as the evil one sought to make Jesus worship him (see also Luke 4:5–7), but resisted. The saints of all ages follow this example (Acts 5:41; 1 Peter 2:21), for they know Satan is defeated.
12 Here is a call for the endurance of the saints, those who keep the commandments of God and their faith in Jesus.