If Lucifer had never rebelled then there would have been no need for the sacrifice of God's only begotten son, Christ. If Lucifer had been willing to perform the task God had set for him, he would have helped billions of souls achieve Buddhahood, or another way to say it, their God consciousness, instead he chose to rebel against God's plan. Chester tried to find a flaw. The Master looked sad. God knew Lucifer would deceive mankind just like Lucifer deceived the Angels in his charge.
Lucifer is the spirit of deception.
If Lucifer could get mankind to destroy themselves and their planet, then no more Buddha's. Buddha achieved enlightenment by taking the path of renouncing the world and becoming homeless as a way to become non-attached to this world of matter. The path of non-attachment is very difficult. Most people aren't willing to do that. That is where the Sabbath comes into the Plan of God.