Parashat Korach details the famous story of the Korach rebellion. The Torah states (BeMidbar 16:1), “VaYikach Korach Ben Yitzhar Ben Kehat Ben Levi,” “And Korach, the son of Yitzhar, the son of Kehat, the son of Levi took.” Why did the Torah spell out Korach’s lineage all the way up to the tribe of Levi, but stops short of Ya’akov, Levi’s father? Rashi (ad loc. s.v. Ben Yitzhar Ben Kehat Ben Levi) states that when Ya’akov was blessing his sons before his death, he placed a personal plea into the blessing bestowed upon Levi. Ya’akov stated (BeReishit 49:6), “In their assembly [Korach and his cohorts] do not mention my name.” The Kli Yakar (ad loc. s.v. VaYikach Korach Ben Yitzhar etc.) explains that a forefather's name mentioned in the lineage implies that the root of the descendants’ actions can be found in the predecessor. Therefore, it would be inappropriate for the Torah to list Ya’akov, a Tzaddik, in the lineage of Korach, a sinner.
However, the question still remains of what exactly Korach’s intentions were with this rebellion. A possible answer lies in Moshe’s appointment of a Nasi (tribal leader). Moshe had appointed Elitzafon, the son Uziel, to be the Nasi of Kehat. Elitzafon’s father, Uziel, was younger than Korach's father, Yitzhar. Korach therefore felt that the position of Nasi should have been dedicated to him since his father is older than Elitzafon’s.
Despite this rebellion, Korach is not considered a Rasha. This is hinted to us in the words of Tehilim (92:13), “Tzadik KaTamar Yifrach,” “The righteous will blossom like a date palm.” The last three letters of these three words spell Korach. Korach truly believed that he should be the Nasi out of respect for his father's honor and not his own. Korach didn't realize how powerful the Middah of jealousy is. In his heart, he was jealous of having been passed over for a position that he felt he rightfully deserved. This jealousy led him to persuade two hundred and fifty men to rebel against the validity of all of Moshe's appointments, including Aharon’s appointment as the Kohein Gadol.
With this we can understand why Korach's father, Yitzhar, was mentioned. The start of Korach's uprising was his claim to the Nasi position as the son of Yitzhar. Korach's lineage also extended to Levi, as it was an aspect inherited from Levi that played a role in his jealous uprising. Levi was a coconspirator with Shimon in their plan to harm Yosef. Levi allowed his jealousy regarding Ya'akov's favoritism to profoundly disturb him. The lineage therefore extended to Korach. Korach, just like Levi, let his jealously get the better of him. Although he believed he was justified in his actions, it had detrimental results. The Middah of jealousy is one which can control people and bring out the worst in them. It is therefore imperative that we work to fix this Middah so we don’t fail like Korach.