phos and zoe - light and life
Phos is Greek for 'light' and Zoe is Greek for 'life'. The Phos Zoe Cross symbolizes the light and life of Christ. The nature of light is that it cannot help but banish darkness. God's Light in Christ enables us to see spiritual truth.
The nature of life it that it is the opposite of death. Our human life will come to an end, but in Christ, our spiritual life will last forever.
"In Him was life, and the life was the light of men. The light shines in the darkness, and the darkness has not overcome it." John 1:4