The book of Deuteronomy begins by telling us that Moses spoke these words “to all of Israel.” As the Vilna Gaon points out, it is obvious they were spoken to all of Israel, but the phrase is included because there are shades of meaning.
The words of Torah are simple and available to all. The phrase “all of Israel” also means that they are infinitely deep, and each person can comprehend them according to that individual’s capacity.
“All of Israel” also implies an eternity. It was not only spoken to the Israelites standing before Moses that day, but to all Israel for all time. Moses speaks to us as he spoke to his contemporaries.
Finally, even though the words are different to different people, and have special resonance in each soul, they are given to an entire people. The Torah is a spiritual covenant for an entire people; it teaches Israel how to move through the wilderness and through the world. We are in this together.
All that and more is contained in a simple, easily overlooked phrase that was given to us, all of Israel.