TT #76 · Parashas Vayeira · Passuk 20:17
And Avraham prayed to God, and God healed Avimelech and his wife and his maidservants, and they bore children.
Torah Temimah points to Bava Kama 92a. E-Daf · Sefaria — Bava Kama 92a
TT lemma: ויתפלל אברהם.
“And Avraham prayed.” From where do we know that one who is asked by his fellow for forgiveness and does not forgive him is cruel? As it is said, “And Avraham prayed to God.”
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The act of intercession is taken as the paradigm of granting mechilah.
One who refuses to grant forgiveness when properly asked is called cruel; Avraham’s prayer for Avimelech is the proof that forgiveness should be given.