This document contains a seminal letter from December 25, 1972, written by philosopher Ladislav Hejdánek to the leadership of the Evangelical Church of Czech Brethren, followed by a 2009 exchange with theologian Jakub Trojan. In the 1972 letter, Hejdánek delivers a passionate, prophetic critique of the institutional church's attempts to survive through political compromise during the normalization period in Czechoslovakia. Written in a state of high fever and spiritual urgency, he warns officials against a 'false path' of self-preservation that betrays the Gospel's call to witness the Truth and embrace the 'church of the cross.' Hejdánek argues that the church exists to sacrifice itself for the Truth, not to navigate political survival through lies. The 2009 correspondence contextualizes the letter's history, revealing it was originally a recording shared within the 'New Orientation' movement. Together, these texts provide a profound insight into the internal moral and theological struggles of the Czech underground church under Communist rule.