What does the Bible say about spiritual blindness and deafness?

Scripture presents spiritual blindness and deafness as a condition of all humanity due to sin. Isaiah 29:18 prophesies that in the coming of Christ, the deaf will hear and the blind will see. In Mark 7 and 8, we see Jesus physically healing a deaf man and a blind man, which symbolize the greater spiritual healing He offers through the Gospel. Without Christ, individuals are unable to perceive their need for salvation or understand God's truth, akin to being deaf and blind. Only through the preaching of God's Word can their eyes and ears be opened to the reality of their sin and the necessity of Christ's redeeming work.