NET

19 Moreover, we possess the prophetic word as an altogether reliable thing. You do well if you pay attention to this as you would to a light shining in a murky place, until the day dawns and the morning star rises in your hearts.

Darby

19 And we have the prophetic word [made] surer, to which ye do well taking heed (as to a lamp shining in an obscure place) until [the] day dawn and [the] morning star arise in your hearts;

KJV

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: