I read on shirat devorah the following:
1) The Midrash tells us that G‑d told Abraham: “If atonement is not granted to your children on Rosh Hashanah, I will grant it on Yom Kippur; if they do not attain atonement on Yom Kippur, it will be given on Hoshana Rabbah.”
Where does the Midrash say this?
2) Isaiah says, “They seek Me day [after] day.”
Where does Isaiah say this?
The Talmud explains that these two “days” refer to the day when the shofar is sounded [Rosh Hashanah] and the day when we take the willow [Hoshana Rabbah]—the day when the heavenly judgment begins, and the day when it concludes.
Where does the Gemara say this?