What does it mean to keep the faith?

Acts 26:18 I believe by keeping the faith it means simply to continue trusting in christ. and not our own minds. Our minds continue to attack the Christian faith and thoughts so choosing to daily surrender to the words of Jesus : Collosians chapter 3 -tells how to live the christian life daily. Continue to be led by the holy spirit and not our own thoughts is "keeping" the faith in Christ.