Musar for Niddah 125:19

And it is because of the difficulty of studying, and concentrating and discussing keenly that many people abandon the study of the Talmud, because of the difficulty of understanding its tradition and its grammer when taught orally, for they say, "How can we understand all of these opinions that come from outside the book itself? Would that we knew what is in the books!" Yet if they would study at fixed times, day and night, then they would learn and be completely familiar with the Talmud and they would develop a strong desire to study, for then they would have mind to understand things easily, and a man would then come to study constantly whether sleepy or awake and they would acquire through this means a complete reverence for God. And then pupils would increase and they too would occupy themselves constantly with the Torah. But now, because of the great difficulty of understanding the tradition when taught orally, the study of the Law has become a heavy burden to them, and they cannot look at the Talmud any more, and because of this they occupy themselves with madness and frivolity, and they are confused and they waste their time and they engage in all sorts of scheming plans, and they have no fear of Heaven.