There is a certain frustration we have all run into when arguing points with someone whose views are opposite to our own. Eventually the other party may come out with the line, "I don't trust your sources." There's not a lot you can say after that, since what they are really saying is, "What is true for you is not true for me." They have decided that your sources are unreliable, and so they are invalid. You may think the same about theirs.
It all boils down to trust. When we trust our sources, we are confident in what we believe. When valid doubt is cast upon their reliability, we find ourselves standing on sand. Edith Stein, a Jewish convert to Catholicism and a respected intellectual of her time, recognized the truth when she read it. She was so convinced that she went on to be martyred in a concentration camp and became St. Theresa Benedicta.
Trust is a basic part of life. Anyone who says, "I don't trust anyone" is a liar, unless of course, they don't have a bank account where they trust their money is there, don't expect anyone to stop at stop signs because they can't trust anyone to obey the law, or don't own anything because everyone is a virtual thief anyway. You'd turn into a crazy, paranoid anarchist if you didn't trust even some basic law-abiding ideas.
Some people cast doubt on anything from ancient history. Why make a distinction between what happened millennia ago and what happened yesterday? If we don't trust basic scholarship that has stood the test of time, then all history, even the most recent, ceases to have any meaning.
If we are honestly seeking the truth, we will look it in the face even when it disagrees with our most cherished assumptions. If we don't sometimes react with, "Rats!" when we find ourselves in opposition to the truth, then we must be on the road to sainthood. When we make ourselves the highest authority, then we will never find the truth, but we will insist on going our own way, and that is tragic. And we will have repeated the original mistake by making ourselves god.