Parshas Emor, Likkutei Sichos lamed zayin, page 67 This sicha dives into Torah's mention of Shlomis bas Divri and her illicit relationship with an Egyptian man. Rashi tells us this is mentioned to praise the yidden that this was the only time this happened, and that there were no arayos within the yidden at this time. But still, why would Torah use this negative instance to highlight a positive praise of the yidden? This can be compared to someone doing true teshuva - a past negative now becomes like a merit. Something negative can happen but when that is a growth point, a springboard for positive growth & action, then the negative thing takes on positive purpose. In todays time this is a way that we can even elevate shalosh klipas hatamayus. If a person does such great teshuva that his past actions become now true zchusim, then this elevates the past klipah. There is no such thing as a lost case. We are in golus, people make mistakes, so then what? We dont give up, we use it a springboard for teshuva, and this uplifts the past. Looking back, there is purpose for the difficult or negative things someone may end up involved in - moving forward, we use it to grow even closer to Hashem, even more kedusha. And when we look at someone else, we dont write them off, our job is to highlight the good, take that persons negative story and highlight the zchusim in it.