Transfiguration

Matthew 17:2 - And he was transformed before them, and his face shone like the sun and his robe became as white as light.

In a time and place without electricity or very good laundry (did they even clean their clothes? poor slaves), whiteness and light were symbols of purity. I'm pretty sure this is why we still think of those things as pure. Light gives us eyes, helps us see. This transformation signals to us that Jesus is otherworldly - He is God in the flesh.

They are seeing God/Jesus as he truly is. And they live. They don't yet understand, but they live.
B