Basing his calculations principally on Daniel 8:14: "Unto two thousand and three hundred days; then shall the sanctuary be cleansed", Miller assumed that the cleansing of the sanctuary represented the Earth's purification by fire at Christ's Second Coming.
Întemeindu-se pe profeția din Daniel 8:14, după traducerea KJV ("Unto two thousand and three hundred days; then shall the sanctuary be cleansed."), Miller a înțeles curățirea sanctuarlui ca fiind purificarea pământului prin foc la a doua venire a lui Iisus Hristos.