Naruto: Shippuuden (dub) Episode 120

The episode picks up with Kakashi and Obito Uchiha at odds over how to handle the kidnapping of their teammate, Rin Nohara. While Kakashi initially insists on prioritizing the mission, Obito's words— "Those who break the rules are scum, but those who abandon their friends are worse than scum" —eventually change Kakashi's mind.

This episode marks the definitive shift in Kakashi's personality from a cold, rule-abiding soldier to the comrade-focused mentor we see in the main series. Naruto Shippuuden (Dub) Episode 120

You can find the English dubbed version of this episode on major streaming platforms: (Availability varies by region) Hulu (Common for US viewers) Netflix (Select regions) The episode picks up with Kakashi and Obito

Kakashi arrives just in time to save Obito from a hidden Stone Ninja, losing his left eye in the process. Inspired by Kakashi's sacrifice, Obito awakens his Sharingan for the first time, allowing him to see through the enemy's camouflage and kill the attacker. You can find the English dubbed version of

It clarifies why a non-Uchiha like Kakashi possesses the Doujutsu.