When we are sick we do not want a doctor to give us his interpretation in diagnosing what is wrong with us or what is the correct medicine to use to cure what ails us. We want the correct and accurate account of what is wrong with us as well as the correct medication to use to heal from our afflictions.
The same with the Bible—we do not want someone’s interpretation or idea of what God is saying. We want the truth so we know what God is actually saying and so we know what we are to do and believe in order to obey God and be cured of the sins which afflict us.
In getting the truth, we also get the peace that passes understanding that the Bible talks about because we know we got the correct information and are abiding by it.