Bringing Nachas Ruach to Hashem:
The Imrei Emes zy”a (quoted in Sefer Likutei Yehuda) explains this pasuk with a story that is said about the Chozeh of Lublin zy”a. (According to some versions, this story is said about the Yid Hakadosh of Peshischa zy”a.) It is related that the yeitzer hara once attempted to persuade the Rebbe to do a certain act, and tried to convince him that this action was completely permitted. However, he refused to do it since he could not see any way that this act would create a nachas ruach for Hashem, and he would not do anything that did not bring pleasure to Him.
So too, Yehuda was saying: “What is there to gain?” Even if you are correct that it is permitted to kill Yosef, how will this create a nachas ruach for Hashem?
