Ye do well that ye take heed

"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:"
(2 Peter 1:19)

The importance of taking heed. (Paying careful attention, taking notice of)
While there are some things we are exhorted NOT to take heed to, the text speaks of what we do well to take heed to.

1/ Why we do well to take heed to the word of God.
2/ Other things we are especially warned to take heed to in scripture.