guru - a medium

Hi, Basically, I wanted to know the meanings of: 1. "mein apan bol na jaanda mein keha sab hukmai jiyo " 2. "Jaise mein aavey khasam ki bani, taisda karin gyan veh lalo." I think they have been said by Guru Nanak and are a part of the Granth Sahib. What exactly do they mean and what is the...