The pace against Jesus is picking up. People reported the Lazarus affair to the religious leaders. Now they want to kill Lazarus, too.
I had always thought of Caiaphas' words as a clear statement of substitutionary atonement. But they look much more sinister, like a murderous motivational speech. After this they set out to kill Jesus themselves. These were the determining words in the death sentence of Jesus!
Jesus protected Mary for her extravagant worship. People who would go all the way with Jesus may need protection from their critics. John and Jesus both expose the hypocrisy of Judas about the money spent on the perfume.