'Understand' in the Bible

But understand this first of all, that no prophecy of Scripture is a matter of or comes from one’s own [personal or special] interpretation,

First of all, know [without any doubt] that mockers will come in the last days with their mocking, following after their own human desires

speaking about these things as he does in all of his letters. In which there are some things that are difficult to understand, which the untaught and unstable [who have fallen into error] twist and misinterpret, just as they do the rest of the Scriptures, to their own destruction.