In plain words
In the Bhārata war, Kṛṣṇa is the charioteer. Arjuna sat behind. He gives Arjuna many teachings. Seeing his kinsmen fighting on the Kaurava side before him, Arjuna sinks down, through attachment and possessiveness, at the thought that he would have to kill them. Kṛṣṇa saw that sight. The war went on for four days. After that it went on for another four days. On the ninth day Arjuna sinks down still further. Kṛṣṇa is guarding him so that none of the weapons that Bhīṣma, fighting for the Kauravas, is loosing falls on him. Kṛṣṇa's whole body became a mass of blood. Arjuna saw this sight. ‘Kṛṣṇa! So many kinds of pain for You, for my sake! I do not want this war at all’: with that he laid down his weapons and slumped to the ground. If Arjuna grew weak at this moment, it would lead to utter defeat. ‘This cowardice is not good for you. Even if you give up the war, I will not give it up’: with that Kṛṣṇa rose up firmly. What is He saying to Arjuna?
As He sprang, the gleam of His earrings spread over the whole expanse of the sky; unable to bear His leap, with the worlds within His belly, the earth shook under their weight; discus in hand, He came rushing on, the yellow cloth upon Him slipping; I trusted in You, do not make my strength a mockery, forgive me, so saying, Kirīṭī drew Him back again; flashing like a lion leaping at an elephant,
Bhīṣma saw Kṛṣṇa coming in that way.