Names Gained by Good Deeds and Lost by Bad Ones

Another interpretation: at first they called him Hosea, as it is said below, "of the tribe of Ephraim, Hosea son of Nun" (Numbers 13:8); and when he did good deeds they added one letter to him, as it is said, "And Moses called Hosea son of Nun, Joshua." And so you find with Jethro: at first they called him Jeter, as it is said, "And Moses went and returned to Jether his father-in-law" (Exodus 4:18); and when he did good deeds they added one letter to him and he was called Jethro. And so you find with Abraham our father, "And your name shall be Abraham"; and likewise with Sarah. And there are others from whom a letter was withheld. You may learn from Ephron, that at first they called him Ephron [with a vav], and when he weighed out the price of the land from Abraham, one letter was withheld from him and he was called Ephran [Efron, written defectively]. And so you find with Jonadab, who at first was called Jehonadab; and when he came to that deed, one letter was withheld from him and he was called Jonadab, as it is said, "When you joined yourself [with Ahaziah]" (II Chronicles 20:37). From here the sages of blessed memory said: a person should not join himself to a wicked person, even to bring him near to the Torah.