Several reasons.
Saw this crusade as a blessing from God.
Christians would stop fighting themselves.
Christians that would fight would go to heaven or be right with God.
To take back the holy lands, from the Muslims would be a righteous cause.
The Phoenicians imported so much papyrus from Egypt that the Greeks used their name for the first great Phoenician port, Byblos, to refer to the ancient paper. The name Bible, or "the book," also derives from Byblos. Today, Spencer Wells says, "Phoenicians have become ghosts, a vanished civilization."
The Provisional Government chose to keep Russian troops involved in WW1 after the Russian revolution (1917) because, having made promises to its allies in 1914, believed they should honor them.
This resolution ultimately proved fatal. In June 1917, the Provisional Government ordered an attack on Austria, which failed. After that, people started to turn against the government. By the end of July 1917, the Provisional Government was almost powerless.
