Nitzavim #3

"Rather, the matter is very near to you, in your mouth and in your heart, to perform it." (30;14) Rashi (30;14) explains that the pasuk is referring to both the written and oral torah.

The Shela Hakodesh explains that for learning the written torah one receives reward for merely saying the words. For the oral torah, however, one must actually understand the words he's saying.

Rabbi Yochanan Zweig explains that Rashi knew that the pasuk was referring to the written and oral torah from the words "in your mouth and in your heart." And how is that? The words "in your mouth" refer to the written torah, as one only needs to say the words in order to receive credit for learning torah. Then, the words "in your heart" refer to the oral torah, as in order to receive credit for learning the oral torah one must take it to heart and truly understand it.

Rabbi Zweig explains from here that whenever we learn Gemara or any part of the oral torah we should make sure that we truly understand everything we say because otherwise we are basically doing nothing.