תּלמוד אויף שמות 32:32

R' Nachman bar Yitzhak said it is from here... (Exodus 32:32; Moshe asking Hashem to have mercy on Bnei Yisrael after the Golden Calf) "And if not, erase me from your book that you have written." "Erase me"--this is the book of sinners. "From your book"-- this is the book of the tzadikim. "That you wrote"--this is the book of the beinonim.

Samuel said: It teaches that Moses jeopardised himself unto death on their behalf ; as it is said, "And if not, blot me, I pray Thee, out of Thy book which Thou hast written" (Exod. xxxii. 32).