Finished Mystery and ceased printing the books. In 1928 Russell's teaching that the natural Jews would be restored to Palestine and hold a prominent place in the earthly part of God's kingdom was dropped. Christmas celebrations ceased in 1928 after a radio broadcast and Golden Age articles on their pagan origins. In 1929, Rutherford announced that the vindication of God's name—which would ultimately occur when millions of unbelievers were destroyed at Armageddon—was the primary doctrine of Christianity and more important than God's display of goodness or grace towards humans. By 1933, the timing of Christ's parousia and the start of the "last days" had been moved from 1874 to 1914 with the principles of parallel dispensations retained to place Christ's enthronement 3½ years later in 1918. In 1935 a new interpretation of the "great company" of Revelation 7 placed them on earth as survivors of Armageddon rather than in heaven and from that point converts to the movement were generally identified as those who, if worthy, would qualify for life on a paradise earth. In 1935, Witnesses were told they should refuse to salute the flag, stand for the national anthem, or accept alternative service provided for those who had conscientious objection to military service. Reference to the cross and crucifixion in Watch Tower publications ceased in 1936 when it was asserted that Christ had actually died on a tree. By 1939 Watch Tower publications explained that only those who were part of God's "organization" would be spared at Armageddon. Persecution and opposition From 1927 onwards, Bible Students were urged to extend their door-to-door preaching to include Sundays. The move quickly attracted opposition from the clergy. In 1928 Bible Students began to be arrested in the U.S. for breaching local by-laws on Sabbath observance. Rutherford challenged the laws in courts, ultimately fighting hundreds of cases in New Jersey alone as he insisted the preachers were not selling literature, but distributing it for a contribution to Society funds. In 1935, Witnesses were told they should refuse to salute national flags, stand for national anthems, or accept alternative service provided for those who had conscientious objection to military service. In late 1936 U.S. schools began expelling Witness children who refused to salute the flag. When the U.S. Supreme Court affirmed the right of schools to expel non-conforming children in June 1940, many states began passing laws requiring compulsory flag salute and similarly