“All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works.” —2 Timothy 3:16, 17
But equally important is to look at the verse in context with all other verses on the same subject. God's Word never changes, and certainly never contradicts itself. If we believe this, then we can have parameters for interpreting Scripture. God cannot lie. If He says one thing in one part of the Bible, He cannot be saying something else elsewhere. Only one understanding can be the right one.
When we study the Bible, we must not ignore parts of the Bible that don't suit us, or discard portions of the Bible as not applicable, or add our own words to it. If we come across a text that seems to contradict other texts, we can safely assume that we do not have a complete understanding of the doctrine that is being studied. Reading the text in context is important.