The Buddha said to judge the action both by the intention behind it and by the result. The two are intertwined. In other words, it’s not just a question of the goodness of your heart. Simply having a good intention is not enough.

"One of the old questions in ethics is how to judge an action. Do you judge it by its intention or it by the result? As usual, the Buddha found a way of not falling for that dichotomy. He said to judge the action both by the intention behind it and by the result. The two are intertwined. In other words, it’s not just a question of the goodness of your heart. Simply having a good intention is not enough. It sets you in the right direction, but you’ve got to learn more than just having good well-meaning intentions. At the same time, it’s not just a question of being effective regardless of what your intentions is. You want to be skillful all around.

In this way, the Buddha takes the question out of the realm of ethics and into the realm of skill. As any craftsman or craftswoman knows, a good piece of art is accomplished not just by intending to do a good piece of art or by working from a good idea. It has to be good in the execution as well. At the same time, good execution of a bad idea doesn’t yield good art. The intention and the execution have to work together. There has to be a process of learning over time, as your skills get better and as your understanding of what you’re doing gets better.

This is the type of knowledge we’re trying to develop here: the knowledge comes from doing. Ajaan Lee has makes this point many, many times in his talks. As he says, learning to be a good meditator is like learning how to sew, learning how to weave a basket, learning how to make clay tiles — the list goes on and on and on. You make the object, then you look at it and you figure out what still needs to improve. Then you go back and you do it again. And again. And again. We’re not operating on the pattern of simply arriving at an act of judgment. In Buddhism there is no final judgment, but there is, however, the ultimate development of skill. And that’s what we’re working toward all the time.

We begin with the right intention, the attention to be truthful, the intention to be sincere in trying to give rise to a happiness, trying to put an end to suffering. So before you do anything, ask yourself: Where is this action going to go? If it’s going to give rise to harm, you don’t do it. But if it seems harmless, you go ahead and do it. But then you watch what’s happening as you do the action, because sometimes the results of the action come out immediately. If you see anything harmful coming up, you stop. If you don’t see anything harmful, continue until you’re done.

But then when you’re done, you look at the long-term results. If you realize, contrary to expectations, that something harmful resulted, you learn from that. Resolve not to do it again. Develop a sense of shame around that — shame here not being focused on your sense of yourself as a bad person, but on the action. You realize that was a shameful action — either ignorant in the intention or shoddy in the execution — and you’d be ashamed to do it again. This is actually a sign of high self-esteem, that you’re better than that kind of action.

If you see that what you did caused no harm at all, then take joy in the fact that you’re on the path — joy in a sense of pride in craftsmanship. And even though ultimately we’re trying to get rid of pride, we use it on the path as nourishment when we’re sure we’ve done something right. But we keep on training. In other words, you look again and again and again each time you act, because sometimes you find that what seemed okay the first time around is not okay the second time or the third."

~ Thanissaro Bhikkhu "Mastery"