I understand that many strains of Christianity hold that a sinful thought is still a sin – as Jimmy Carter reminded us. And that while Judaism does not exactly encourage sinful thoughts, we consider what we say or do (our conscious choices) to be far more significant.
But until now, I had not realized that there is a textual basis in the Torah for either position. The key word is yetzer, a word which means “devised” or “created with planning.” Yetzer is the word used to describe G-d’s deliberate creation of Adam and the animals.
But in the hands of mankind, yetzer has darker application. Here are the verses in which it is used:
G-d saw that great was humankind’s evildoing on earth and every yetzer of their heart’s thoughts was only evil all the time.
And so G-d punishes man – for our very thoughts. He destroys everyone but Noah and his family – and at least in part for what amounts to thought-crime.
But then the Flood takes place, and Noah offers an elevation-offering to G-d afterward, essentially a promise that mankind will try to do better in the future. And G-d does something that I think not everyone who reads the text notices: G-d changes His mind about how man will be judged! The text gives it to us straight:
G-d smelled the soothing savor, and G-d said in His heart: “I will never curse the ground again on humankind’s account, even though the human heart yetzer is evil from its youth; I will never again strike down all living-things, as I have done.”
In other words, G-d changes the terms of the deal. After the flood, man is never judged again by G-d for what we think of doing. Instead, every judgment comes about as a result of the choices made after we consider our instincts, desires, and lusts – and then our conscious minds decide what we should say or do.
After the Flood (and in the Torah) G-d no longer judges mankind by our thoughts. Which suggests that there is textual support for the Jewish position that sinning in our hearts – as long as it does not escalate to words or deeds – is no sin at all.