I heard a drasha on Shabbos from a kiruv rabbi, who talked about the importance of changing yourself upon repentence and becoming a new person. He hooked it into last week's parsha by quoting our ancestor Sara's denial of God's accusation that she laughed upon hearing the unbelievable news that she would give birth at such an old age. The idea was that when she said lo’ tzahhaqti
, "I did not laugh" she was telling the truth — she was ashamed at her previous action, and transcended it, becoming a new person. The new "I" was not the same Sara who had laughed.
What the speaker forgot, though, is the end of the verse. Read it
. God responds to Sara's denial, her supposed new identity, with three words: lo’, ki tzahhaqt
. No, you did laugh. You can't deny your past. You can change yourself, you can move on, and you can improve. But you can never deny who you are, who you were, or where you came from. That's not what teshuva