In plain words
Out of jealousy that there was an archer greater and mightier than himself, Arjuna told Droṇa, “Ask him for some guru's fee.” Wishing to satisfy Arjuna, Droṇācārya asked Ekalavya, “What will you give me as the guru's fee?” Then it was Arjuna again, to Droṇa: “He said he learnt this archery thinking of you as his guru. So you too must be the cause of his archery being broken,” he said. Then Droṇa asked him for the thumb of his right hand. At once Ekalavya severed the thumb of his right hand and gave it as the guru's fee. Ekalavya did not grieve at all that his archery was broken; he rejoiced greatly: “I have fulfilled my guru's wish.” From that day Ekalavya never took up an arrow. Arjuna was very glad. And with it Ahaṅkāra grew in him, that besides Arjuna there was no one else in this world who knew how to shoot at a sound.
Because he gave his right thumb as the fee, his deftness in setting arrow to string was broken; the forest archer fell from his wealth of archery, and the ache in Pārtha's heart was gone at once.
Today many people are trying to know the principle of the Ātma. Only when you give up the Ahaṅkāra and the attachment of “I and mine” is the principle of the Ātma truly experienced. As long as you keep these two in you, however hard you try, the principle of the Ātma will not be seen. First of all you must give up the Ahaṅkāra that says ‘I’. Only then will your eye of Jñāna open. It was because he gave up Ahaṅkāra that Jesus came to be worshipped. You know it: Christians worship the cross (†). When the neck of the ‘I’ is cut off, it becomes a cross. Its inner meaning is the giving up of Ahaṅkāra. You must recognise that Ahaṅkāra is the root cause of every kind of sorrow, unrest and suffering.