This source is another indication that each year we become pure, and each year we receive the Torah again.
The Shevet Mussar (34:19) discusses what one should have in mind when he listens to the Torah reading in beis medresh. (The Shevet Mussar refers to the entire year, not only Shavuos.) He writes, "Imagine that the bimah is Har Sinai, and you are receiving the Torah on Har Sinai. Hakadosh Baruch Hu and His malachim are present, Moshe Rabbeinu is the baal koreh, and the entire nation is standing around the mountain to hear Torah from his mouth."
Certainly, we should have this thought when we read the Aseres HaDibros on Shavuos (and when we read parashas Yisro and parashas Vaeschanan).
The Midrash (Psikta 12, Yalkut Shimoni Yisro 271) states, "Hakadosh Baruch Hu says to the Jewish nation, 'My children read this parashah [of matan Torah] each year, and I will consider it as though you stood before Me on Har Sinai and received the Torah."
We read the Aseres HaDibros three times a year: Shavuos, Shabbos parashas Yisro, and Shabbos parashas Vaeschanan. The Beis Avraham explains this with a mashal of a very sick person who needed a dose of powerful medications. But he was frail, and the strong medication would harm him. So, his doctor divided the medication into three doses. The nimshal is that hearing the Aseres HaDibros is like a spiritual, powerful cure. However, this spiritual experience is too intense for our weak minds. Therefore, the impact is divided into three so that the Jewish nation could accept it.
When a father speaks to his son, it is derech eretz that the son should face his father. If he turns around and faces the other direction, that is chutzpah. Therefore, when the Torah is read, we should listen with yiras Shamayim and pay attention to the words. If we turn our minds to other matters, that is chutzpah.
We should want to receive the Torah. There is a mashal of a person from a third world country who came to a developed country, and saw someone tie himself in ropes, and climb up a pole. The simple man said, "I thought this is an intelligent country, but I see these people are foolish. In my country, they also tie people up in ropes. They do that to someone who breaks the laws of the land. But people of my country are intelligent. They won't tie themselves up willingly. But I see in this land, people willingly tie themselves up in ropes, to be hung!"
A local explained to him that this person isn't going to be hung. He is an electrician. He is climbing up the pole to fix a lightbulb. He is tying himself with ropes so he won't fall.
The nimshal is that the halachos of the Torah are limiting, and some people feel it is hard for them. The Torah doesn't allow them to go where they want, look where they want, and so on. But these limitations are for their benefit so that they won't fall. Being cautious with the laws of the Torah protects them, and a great light of kedushah comes from it.
It states (Vayikra 19:19) וחזק הולך השפר קול ויהי מאד. Rashi explains that the blast of the shofar became consistently stronger and stronger. "When humans blow a shofar, the longer one blows, the weaker the sound becomes. But here, it became stronger and stronger." Hinted in these words is that the matan Torah of every year becomes stronger and greater than the previous years.
