Like the Christians who were physically persecuted in the New Testament. Like our maintaining devotion to Christ when family and friends oppose and discourage that devotion. Faith is commitment. Like Paul's commitment to teach people about Jesus. Faith is fidelity to God, being true to God regardless of circumstances.
Faith also involves some paradoxes.
A paradox involves two statements, two expressions in a concept, that are contradictory yet true. It would appear that if one is true the other would have to be false. Yet, even though it cannot be fully explained, both are true though they appear to contradict each other. However, though faith is intangible, you can observe its existence. You cannot look at or touch the faith.