This is the Story of Ekalavya
In the Hindu epic Mahabharata, Ekalavya (Sanskrit: एकलव्य) is a young prince of the Nishadha tribes,who nevertheless aspires to study archery in the gurukul of Dronacharya
Eklavya was a small bright boy who lived near the ashrama of Drona, where Pandavas and Kauravas used to take lessons in various arts. He had great desire to learn the art of archery from Dronacharya. But his mother had told him that Drona would not accept Eklavya as his disciple. It was futile to dream of such a privilege. But the boy was not be put off, his determination knew no bounds.
After being rejected by Drona, Ekalavya embarks upon a program of self-study in the presence of a clay image of Drona.
Ekalavya goes off into the forest where he fashions a clay image of Drona. Worshipping the statue as his preceptor, he begins a disciplined program of self-study. As a result, Ekalavya becomes an archer of exceptional prowess, comparable to even to Drona’s best pupil, Arjuna.
. He achieves a level of skill superior to that of Arjuna, Drona’s favorite and most accomplished pupil.
One day while Ekalavya is practicing, he hears a dog barking. Before the dog can shut up or get out of the way, Ekalavya fires seven arrows in rapid succession to fill the dog’s mouth without injuring it. The Pandava princes come upon the “stuffed” dog, and wonder who could have pulled off such a feat of archery. Searching the forest, they find a dark-skinned man dressed all in black, his body besmeared with filth and his hair in matted locks. It is Ekalavya, who introduces himself to them as a pupil of Drona.
Arjuna feared that Ekalavya had eclipsed him in skill with the bow. Arjuna complained to his teacher Drona, reminding Drona of his promise that he would make Arjuna his best pupil. Drona acknowledged Arjuna’s claim, and went with the princes to seek out Ekalavya. He found Ekalavya diligently practicing archery, as always. Seeing Drona, Ekalavya prostrated himself and clasped the teacher’s hands, awaiting his order.
Drona eventually comes to know the same and goes to Ekalavya and demands that Ekalavya turn over his right thumb as a teacher’s fee.
Drona asked Ekalavya for the deed of gratitude a student owed his teacher upon the completion of his training. Ekalavya replied that there was nothing he would not give his teacher. Drona asked for Ekalavya’s right thumb, knowing that its loss would hamper Ekalavya’s ability to pursue archery. It is said that the trees and air around stood still for a minute. Even Arjuna was stunned on listening to the cruel demand of his teacher. To ask for the thumb of an archer was to kill him, inasmuch as it was to divest him of his skill in archery. Ekalavya, however, cheerfully and without hesitation severed his thumb and handed it to Drona.
The loyal Ekalavya cripples himself, and thereby ruins his prospects as an archer, by severing his thumb and giving it to Drona.
Drona is criticized by his own son Ashwatthama & others over this incident. Drona was, as the epic says, protecting the fated superiority of Arjuna.
But Drona Blesses Eklavaya with a boon that till the world remains the name of Ekalavya will be taken first among the Persons who show loyality to their Teachers.