The work of the Holy Ghost by of word of God in the human heart gives light in a dark place. Thus, we preach the Bible.
Preaching the word of god
2 Peter 1:19 We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts:
Life
"In him was life; and the life was the light of men..."
And the light shineth in darkness; and the darkness comprehended it not." [John 1:4,5].
Faith
"Believe the Bible..."
John 20:31 But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name.