And this is the manner of the release: every creditor shall release that which he has lent to his neighbor; he shall not exact it of his neighbor and his brother, because the release of Hashem has been proclaimed.
English: "That which he has lent" — It was taught: Rabbi Shimon says: He himself releases, but his heirs do not release, as it is said "every creditor shall release that which he has lent"—he, and not the heirs.
On the daf / in context: When the original creditor has died, the orphaned heirs are not subject to the same obligation of release.
Type of Learning
Derash on the verse (Sifrei) — heirs are not required to release.
What Is Learned
The obligation to release a debt in the shemittah year falls upon the original creditor, not upon his heirs.