How much evidence is enough to resolve unbelief? Mark 8:11–21 prepares us for the hearing of God's Word, publicly read, in the holy assembly on the coming Lord's Day. In these eleven verses of Holy Scripture, the Holy Spirit teaches us that unbelief is not resolved by more evidence, but by eliminating the unbelief itself. The devotional examines Mark 8:11-21 to find that the root of spiritual blindness is a hardened heart rather than a lack of evidence. The Pharisees' demand for signs results in Jesus's warning against the leaven of unbelief and skepticism. Pastor emphasizes that believers also struggle with doubt, when they judge by external circumstances instead of God's Word, character, and work. True faith requires the Holy Spirit to soften the heart and enable perception. Ultimately, living by faith depends on continual reliance on God's grace to overcome remaining sin.