So many argue about the word apostasy saying man goofed up but I believe God knew exactly what He was doing. The word has two meanings to depart and fall away from the faith.
 When the philadelphia church is taken from the hour of trial they will depart. Those of the 6 churches left will either become the wheat which has to go though trib to bear fruit or will be among many who will fall away from the faith. So apostasy is the correct word to describe the first rapture and the begining of Gods wrath.