Since we have limited knowledge, we need someone or something to depend upon. So, who is your authority, who do you depend upon? People depend on parents, siblings, friends, money, relationships, looks, intellect, philosophers, and themselves. 

Who is your "who said so?" What or who is your authority that you go to when you need to verify or find some wisdom? 

If your dependence is on anything other than God, the God of the Bible, then you are in trouble. God is perfect! Everything that He does has no spot or blemish.