That statement was not speaking of all believers inclusive of those of the old testament times. It was about Christian faith. Christian faith occurred only after the resurrection of Christ. And not all who believe do so with the reasons for basis. We should just trust God. But you cannot be in the dark that there are atheists looking for a field day attacking faith of Christian believers which has no basis in reason. There is certainty with inward witness, that still comes from somewhere. And the Christian faith is not without abundant evidence, and the resurrection of Christ is the greatest of all, with the empty tomb of Jesus Christ after he died, according to his claim before that he would rise from death, his appearance to many followers who all saw him, and those testifying to their death to that, with the changed life of followers with their faith. People of old testament times saw miracles from God which encouraged faith, so they would have faith with their bases, but they didn't understand things of Christ who was yet to come, so they would not have been Christian believers. And faith in Scriptures from God does not do away with reasoning that we should have, so there is not that sola Scriptura that is valid, but with bases the Scriptures can be trusted to be revelation from God, as such, what is shown from them takes priority.