Look
'Look not back behind thee,' as in Genesis 19:17, means that Lot, who represents the good of charity, should not look to matters of doctrine. 'To look up,' is to look to celestial things. In Genesis 18:22, looking signifies thinking because seeing denotes understanding.
(References: Arcana Coelestia 2245)
Great lights
Great lights, as in luminaries, signify love and faith, and are called in Genesis 1:14-17 the sun, moon, and stars.
(References: Arcana Coelestia 31 [1-3])