"The blacker the night the greater the need for a light bulb.

If the bulb does not shine, it's not because of the darkness. Darkness cannot put out a light. ... Darkness gets darker because the light fails."

~ Haddon W. Robinson, "The Christian Salt and Light Company"

The world was dark to begin with and God created light. The universe's tendency is toward darkness, so in order to overcome darkness, the light needs to shine brighter and to keep shining and to multiply.

"In the beginning, when God created the universe, the earth was formless and desolate. The raging ocean that covered everything was engulfed in total darkness, and the Spirit of God was moving over the water. Then God commanded, “Let there be light” — and light appeared. God was pleased with what he saw."

(Genesis 1.1-4 GNB)

When a Christian gives in to worldly desires and compromises, her / his light dims. And when this spreads, it reduces the brightness of the collective lights.

Dear God,
please help me safeguard my light
may I shine bright for your glory
and keep on shining

See: Infestation