During the reign of Hazrat Uthman Radiallahu anhoo
During the Caliphate of Hazrat Uthman Radiallahu anhoo both Hazrat Hasan AlahisSalam and Hazrat Husain AlaihisSalam were completely mature. Now, both these gentries also started participating in the crusades. Hence during Hijri 30, they took part in the movement of Tabaristan.
When Hazrat Uthman Radiallahu anhoo was encircled by the rebels, Hazrat Ali AlaihisSalam sent Hazrat Hasnain AlahisSalam to protect Amir-ul-Mominin. Both these princes kept standing on the gates and prevented the rebels from entering inside. Nobody could enter from the gate where both these noble and loved children of Huzur best to were standing. All the rebels failed. From the other side, two wicked persons pushed in and killed Amir-ul-Mominin. Had the children of Bani Umaiyya been guarding on all the sides of the house like Hazrat Hasnain AlahisSalam, the rebels could not have succeeded.
During the battle of Jamal
During the battle of Jamal, Saiyedna Imam Hasan AlahisSalam rendered a great service to, the religion and human community along with the protection to the Caliphate. He went to Kufa with Hazrat Ammar-bin-Yasir Radiallahu anhoo and delivered a very effective speech in the mosque (Jama-i-Masjid) against the mutiny. Hazrat Ammar-bin-Yasir Radiallahu anhoo also made an impressive speech. Both these speeches inspired people to cooperate Amir-ul-Mominin. The statements they made during their speeches were very much appealing and effective. They said,
“O’ people, worship Allah, the Almighty, respect Hazrat Rasulallah ﷺ and Amir-ul-Mominin. O’ people, Hazrat Ayesha SalamUllahAlaiha is a holy wife of Hazrat Rasulallah ﷺ. But in this respect, Allah, the Almighty wishes to test your faith. Allah wants to see whether you respect Hazrat Ayesha SalamUllahAlaiha or Allah.”
In short, the addresses made by Saiyedna Hazrat Imam Hasan AlahisSalam and Hazrat Ammar-bin-Yasir Radiallahu anhoo were so much powerful and effective that an army of ten thousand people came and stood shoulder to shoulder for the support of these gentries. These brave people, at once, joined the holy army of Hazrat Amir-ul-Mominin AlaihisSalam
During the battle of Jamal, Saiyedna Hazrat Imam Hasan AlahisSalam was the commander-in-chief of the right-wing and Saiyedna Hazrat Imam Husain AlaihisSalam of the left-wing, of Haidari Army.
During the battle of Siffin
Here also he exhibited his spirit of bravery. There was his signature as a witness on the treaty, which was signed after the battle of Siffin.