The most important lesson of the Bhagavad Gita is nishkama karma—performing actions without any expectations of the fruits of action. This is an exceedingly difficult thing to perform practically. One has to act but without self-interest. To do anything well, one has to take an interest in it; so, interest has to be there, but the self has to be absent. Is it possible to find someone who performs such selfless action?
In the Mahabharata, the person who comes closest is Pitamaha Bhishma. He had a long lifespan and witnessed the events of the Mahabharata from the times of Shantanu till the end of the great war. At a very young age, he made a great sacrifice for his father, who wanted to remarry. He took a vow to never stake a claim to the throne and never marry so that there was no possibility of his son staking a claim. For this terrible vow, he came to be called Bhishma and was granted iccha mrityu—the ability to choose the time of his death.
When Satyavati’s elder son Chitrangada died childless, her younger son, Vichitravirya, was a minor. Bhishma could have captured the throne under the pretext of keeping Hastinapur safe. Instead, he put the minor on the throne and ran the kingdom till he grew up; upon which he single-handedly abducted three princesses of the Kashi King to get him married. Vichitravirya died soon without producing any children, so the throne of Hastinapur was again up for grabs.
This time, even Satyavati asked Bhishma to marry the widows of his stepbrother and rule as king. This is the same throne for which the Kauravas and Pandavas fought a war to the finish, two generations later. This throne was Bhishma’s for taking, not once but three times, but he never coveted it; yet he continued to serve the throne to the utmost of his ability till his last breath.
In his position as an elder of the Kuru family, he fearlessly advised the king that was in conformance with the ideals of truth and justice. When his advice was ignored, and the decision was made to go to war with the Pandavas, he followed his duty as a loyal soldier of Hastinapur, despite his belief in the righteousness of the Pandavas. As general of the Kaurava army, he led it heroically for 10 days. In combat, he proved unconquerable, even provoking Sri Krishna to pick up arms; in the end, only succumbing to an Arjuna shooting arrows from behind Shikhandi whom Bhishma had vowed to not attack. It would be difficult to find a better example of selfless work, thus making Bhishma a strong candidate for being called an ideal man.