תְּשׁוּבָה Elul · teshuvah
Teshuvah: the work of the month
Teshuvah isn't simply “repentance”: it is return. Returning to who you are, and returning to Hashem. Elul is the month when that work is done slowly, before Yom Kippur seals it.
The steps, according to Rambam
Rambam ordered teshuvah into clear steps (Hilchot Teshuvah 2:2): recognize what was done, leave it, regret it truly, and resolve not to return — and say it aloud, the vidui, the confession. It is not a vague feeling: it is a path with steps.
Two different debts
The tradition separates two things. What stands between you and Hashem (bein adam laMakom), Yom Kippur reaches. But what you injured in another person (bein adam lachavero), Yom Kippur does not touch until you go to that person and ask forgiveness (Mishnah, Yoma 8:9). That is why Elul is also lived with the phone in hand.
Forty days to do it
The tradition counts forty days from the start of Elul to Yom Kippur — Moses' forty on Sinai. It is not a short time: it is exactly what it takes to look at the year without rushing and to repair little by little.
Sources: Rambam, Hilchot Teshuvah 2:2 · Mishnah, Yoma 8:9 · Exodus 34.
In My Jewish Day, your cheshbon hanefesh each night of Elul: one line, without a whip, to walk teshuvah.