"Goldie!" came the shrill call from downstairs. "Please come already. You promised to play a board game with me. I've got all the pieces set up."
"Wait just five more minutes, Tami," Goldie called. "I'm just about finished."
"That's what you said fifteen minutes ago," Tami protested. Soon she was standing impatiently at Goldie's side. "You still haven't finished your composition?" she complained to her sister who was sitting at her desk in thought.
Goldie looked up from her paper. "All I have left is the last sentence."
"So what's the problem? How long does it take to write one sentence?"
"The last sentence is different. It sums up the entire composition."
In Parshas Vayeilech, we read about the very last positive mitzvah of the Torah. This mitzvah sums up all of the other positive mitzvos of the Torah.
Do you know what this mitzvah is?
It is the mitzvah of writing a Sefer Torah. HaShem commands every Jew to write a Sefer Torah for himself. But most of us are not scribes, so HaShem allows us to hire somebody else to write a Sefer Torah for us.
The work of a scribe is very expensive. It takes a lot of time and effort to write a Sefer Torah. Not all of us can afford to hire a scribe to write a Sefer Torah for us.
So HaShem gave us another way to fulfill the mitzvah. Many people can share in the writing of a single Sefer Torah by purchasing a letter. In this way, fulfilling the mitzvah of writing a Sefer Torah joins us together in ahavas Yisrael.
HaShem commands us about the mitzvah of writing a Sefer Torah with the verse "Write this song [the Torah] for yourselves." HaShem calls the Torah a song, showing us that we should fulfill its commandments with joy and delight.
And this mitzvah brings us to the greatest possible joy - the coming of the Geulah. Our Rabbis told us that we will bring an end to the Golus very soon by joining with other Jews to fulfill the last mitzvah of the Torah.
(Adapted from Likkutei Sichos, Vol. 24, p. 207ff)