Most chapters in Despite Doubt cite Martin Luther, because the man who endured so much Anfechtung has much to teach us about faith and doubt. I found his observation on the first of the Ten Commandments particularly helpful, and I cite it here to encourage you.
Luther observed that the first commandment is “the commandment to believe,” for God is ordering us to put all of our “confidence, trust, and faith in [Him] alone and in no one else.” This command carried Luther through his dark night of the soul and enabled him to counsel others. He reminded doubters that God has commanded them to hope and believe, so their doubts are a form of disobedience. If for no other reason, they must believe in God because He has commanded them. If they still find it hard to believe, they should not despair over their doubts but instead should “humble [themselves] before God, deploring this fact, and in this way begin with a weak spark of faith and strengthen it more and more every day by exercising it in all [their] living and doing” (Despite Doubt, p. 135-36).
When Martin Luther struggled with doubt he reminded himself that belief in God was a command, and the very first one. This command liberated him to believe out of obedience until he could believe out of firm and certain knowledge. And that knowledge was sure to come, for Jesus said, “If anyone chooses to do God’s will, he will find out whether my teaching comes from God” (John 7:17). Obey the truth, and you will eventually come to know even more truth. You will know more than enough to believe, more than enough to put your doubt away (Despite Doubt, p. 171).