Analysis of information sources in references of the Wikipedia article "Cây khổ hình" in Vietnamese language version.
Long before Christians built churches for public prayer, they worshipped daily in their homes. In order to orient their prayer (to orient means literally "to turn toward the east"), they painted or hung a cross on the east wall of their main room. This practice was in keeping with ancient Jewish tradition ("Look toward the east, O Jerusalem," Baruch 4:36); Christians turned in that direction when they prayed morning and evening and at other times. This expression of their undying belief in the coming again of Jesus was united to their conviction that the cross, "the sign of the Son of Man," would appear in the eastern heavens on his return (see Matthew 24:30). Building on that ancient custom, devout Catholics often have a home altar, shrine, or prayer corner containing a crucifix, religious pictures (icons), a Bible, holy water, lights, and flowers as a part of the essential furniture of a Christian home.
Inside their homes, a cross is placed on the eastern wall of the first room. If one sees a cross in a house and do not find a crucifix or pictures, it is almost certain that the particular family belongs to the Church of the East.
Inside their homes, a cross is placed on the eastern wall of the first room. If one sees a cross in a house and do not find a crucifix or pictures, it is almost certain that the particular family belongs to the Church of the East.