There were 250 people who offered up incense. Besides these, there was a large crowd of people whom Korach had won over to his side, with the help of two members of the tribe of Reuben, the brothers Dathan and Aviram. Moses tried to convince these other rebels to abandon Korach’s mutiny.
Never Despair of Anyone
וַיָּקָם מֹשֶׁה וַיֵּלֶךְ אֶל דָּתָן וַאֲבִירָם וגו': (במדבר טז:כה)
Moses arose and went to Dathan and Aviram. Numbers 16:25

Dathan and Aviram had openly demonstrated their animosity toward Moses, accusing him of being a despot and an impostor. Moreover, G‑d Himself had already sealed their punishment, instructing Moses only to save the other rebels from Dathan and Aviram’s impending fate. Still, Moses did not give up hope that his “enemies” would repent, doing everything in his power to influence them to reconsider.

We learn from Moses to always do whatever we can to bring our brethren back to G‑d and His Torah – even when it seems that all hope is lost. This is true even when they are ignoring their faith intentionally, and all the more so when they are acting out of ignorance.1