This text is a 1975 sermon exploring the profound relationship between truth and freedom from a Christian perspective. Drawing on the Gospel of John, the author contrasts the Greek myth of Theseus and Comenius’s "Labyrinth of the World" with the figure of Jesus Christ. He criticizes the tendency to retreat from the world's evils into an inner "paradise of the heart," arguing instead that following Christ requires "doing the truth" within the world, even at the cost of the cross. Truth is redefined not as mere theoretical observation but as an active engagement that exposes pervasive human self-deception and leads to genuine spiritual rebirth and liberation. References to Dietrich Bonhoeffer and Jan Hus highlight the revolutionary nature of truth, which transforms human existence and provides the strength to face external oppression and fear. Written during the Czechoslovak normalization period, the sermon emphasizes the necessity of courage and living authentically in a mendacious society.