Stained glass window by Frantisek Kysela
The three panels depicts 3 of the 8 blessings in Matthew 5:8-10 with words from the Czech BKR Bible, from left to right:
Blessed are the pure in heart: for they shall see God.
Blessed are they which are persecuted for righteousness' sake: for theirs is the kingdom of heaven.
Blessed are the peacemakers: for they shall be called the children of God.