Rosh Hashana 5773

Where do we know that we need to use a shofar for the tekios on Rosh Hashana? The Gemara (R"H 33b-34a) cites a baraisa explaining that we learn it out from the Yovel (Jubilee) year. The shofar's "teruah" is sounded on Yom Kippur of that year. The posuk also points out that this takes place "in the 7th month" (Vayikra 25:9). In regards to Rosh Hashana, the posuk says it is a day of "teruah" in the "7th month" (Bamidbar 29:1). Since both instances use the phrase "7th month", we learn to blow teruahs with a shofar on Rosh Hashana from Yovel.
Why do we have to learn it all from Yovel? Couldn't the Torah have stated to use a shofar by the pesukim of Rosh Hashana?
I would like to suggest that we re-examine the concept and wording of Yovel. At the end of a 50 year cycle, any land sold goes back to the original owner. The posuk says that each person should "return to his family and inheritance" (Vayikra 25:10).
The Hebrew word for "return" is "lashuv". The Hebrew word for repentance is "teshuvah". They contain the same root. When you do teshuvah, you are returning to Hashem from your bad ways.
What the Torah is saying is to take a step back and remember where you came from. You are a Jew and Eved Hashem just as your family members before you were. That is the purpose of ancestral lands returning to their original owners.
The shofar is sounded on that Yom Kippur to emphasize this message to us. The Rambam says the shofar is to wake us up to do Teshuvah.
This is why we blow the shofar on Rosh Hashana, to wave a flag at us to look at ourselves and our past and how we can improve and grow in the future.