The tzaddikim (the righteous) allow us to see their fire through their teachings. Our ruach (spirit) binds with the ruach of the tzaddik when we learn their teachings with excitement. We want to connect our nefesh (soul) with what we are learning. The longer we stay in one sefer (book), we add more holiness to ourselves. The tzaddikim are completely immersed in the Torah portion they are speaking about. Our Torah learning should be alive inside of us.