In plain words
Arjuna took refuge in God, who is selflessness, freedom from Ahaṅkāra, the principle of Prema and the principle of Satya. Whatever strengths he had, since the strength of those he took refuge with was very small, Karṇa too met their fate.
Though one has strength of arm and good strength of Buddhi, without the strength of God he becomes helpless. Karṇa, great as he was, what became of him in the end? Do not forget this good word.
With so many strengths, what became of Karṇa? He did not take refuge in God. He did not become worthy of God's Prema. With however many strengths, what use are they? The Bhārata, the Bhāgavata, the Rāmāyaṇa, the itihāsas and the purāṇas have all taught such sacred morals, made humanness blossom and rooted out animality.
To come near to God, we must first put away the evil feelings in us
Because we have been living these worldly lives for many births, only worldly feelings have been entering us. We are unable to experience the divine, splendid, ever-new principle of God's Prema. A man who had spent a long time in prison, a man who had slept on hard ground, went home as soon as his sentence was over and lay down on silk cushions. Though he lay on silk cushions, sleep would not come to him. Only on the hard ground did he feel at ease. In the same way, sacred, divine feelings do not suit at all one who has spent his time in the dealings of the world, among the guṇas, in worldly work. He does not understand the supremely sweet principle of God. He cannot experience the supremely peaceful principle of God. The root cause of this is the evil feelings, evil thoughts and wicked brooding he went through before. Only on the day he purifies them will these sacred feelings keep entering him.