A Letter Added for Good Deeds and a Letter Withheld for Sin

Another interpretation: at first they called him only Yeter, as it says, "And Moses went and returned to Yeter his father-in-law" (Exodus 4:18); when he did good deeds they added one letter to him and he was called Yitro. And so you find with Abraham our father, that at first they called him only Abram, and when he did good deeds they added one letter to him and he was called Abraham. And so you find with Sarah, that at first she was Sarai and she was called Sarah. And so you find with Joshua: "And Moses called Hosea son of Nun, Joshua." And there are others from whom a letter was withheld. You may learn from Ephron, that at first they called him Ephron [with the full spelling], and once he took the price of the land they withheld one letter from him and he was called Ephron [defectively spelled], as it says, "And Abraham listened to Ephron, and Abraham weighed out for Ephron" (Genesis 23:16). And so you find with Jonadab, that at first he was called Jehonadab, and when he came to that deed they withheld one letter from him and he was called Jonadab. From here the Sages said: let a person not attach himself to a wicked man, even to bring him close to the Torah. "And the shepherds came and drove them away" (Exodus 2:17).