The God of Christianity is One we can keep believing in when we experience suffering. In light of what Jesus did, Markos says that it’s not irrational to continue believing in God when we suffer. A person who does simply “maintains his trust in a God who suffers and saves.” God has revealed His goodness to us in a tangible way (in Christ), and on that basis we trust Him despite our circumstances.
Christians don’t ignore the facts or take irrational leaps of faith in order to believe in God. In fact, we can acknowledge the gravity of suffering (as Christ Himself did) while still affirming that God is loving and all-powerful.