Light is said to be energy and fame and goes upwards. Hence the gift of light, which is energy, increases the energy of men.
ज्योतिस्तेजः प्रकाशं वाप्यूर्ध्वगं चापि वर्ण्यते। प्रदानं तेजसां तस्मात् तेजो वर्धयते नृणाम्॥