God created with light, and dwelt amongst us through temple to bless us. We are to reflect his light back out to all the nations as a blessing to others. That calling is to be the city now, as a microcosm and model of what God will one day do when Jesus returns and his new city comes down to fully redeem us as we live within the new heavens and new earth fully with God. We have been given the tools through the Gospel to live that calling out eagerly.