"I do forgive you, Hester," replied the minister at length, with a deep utterance, out of an abyss of sadness, but no anger. "I freely forgive you now. May God forgive us both. We are not, Hester, the worst sinners in the world. There is one worse than even the polluted priest! That old man's revenge has been blacker than my sin. He has violated, in cold blood, the sanctity of a human heart. Thou and I, Hester, never did so!"
"Never, never!" whispered she. "What we did had a consecration of its own. We felt it so! We said so to each other. Hast thou forgotten it?"
"Hush, Hester!" said Arthur Dimmesdale, rising from the ground. "No; I have not forgotten!"
Dimmesdale clearly points to what was called a sin of "passion" and compares it to a sin of "will." A sin of the will has always been viewed as worse. However Hester goes further saying that what they did had a "consecration." This is a very special word to Catholics; it is the moment in the Mass where bread and win become the body and blood of Christ. But in their case, it resulted from a feeling ("we felt it so"). And there lies the problem: can we create the "right" because we "say" it is so? Can we make actions "moral" because we say we feel they are?
It obviously didn't work all that well for Dimmesdale....
Dimmesdale says that Chillingsworth has committed the worse sin, because he has calculatedly and with premeditation set out to hurt people to get his revenge. While he (Dimmesdale) and Hester have sinned as well, they never meant to hurt anyone.