American Standard Version (ASV):
And we have the word of prophecy [made] more sure; whereunto ye do well that ye take heed, as unto a lamp shining in a dark place, until the day dawn, and the day-star arise in your hearts:
King James Version (KJV):
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: