To answer this question, of paramount importance is the relationship between the characters. What is the relationship between John and Abigail? Well, she is in love with him and, in the past, he succombed to his lust for her and had an extramarital affair with her that he ended. Second, the time period and the prudent values of the people are important considerations when evaluating the significance of this quote. They were very religious in Salem at the time and adultery is a sin.
After you consider those issue, the question then really seeks to highlight John's feelings for Abigail - was it love, lust or both. So, the question that you must consider and why this is of such significance is the reason John got involved with Abigail and then ended the affair with her. If he wasn't married or if he wasn't religious, would he have chosen Abigail over his wife. Was it his over for his wife or his fear of sin that forced him to end his affair? Now, those questions may not have an answer, but they are raised when Abigail is the person who John may hurt. Does he still have feelings for her? Will he always? or Conversely, did he just succomb to one of the seven sins, lust?