Second episode/adhyaya – Saankhya yoga
taṁ tathā kṛpayāviṣṭam
viṣīdantam idaṁ vākyam
sañjayaḥ uvāca—Sañjaya said; tam—unto Arjuna; tathā—thus; kṛpayā—by compassion; āviṣṭam—overwhelmed; aśru–pūrṇa—full of tears; ākula—depressed; īkṣaṇam—eyes; viṣīdantam—lamenting; idam—this; vākyam—words; uvāca—said; madhusūdanaḥ—the killer of Madhu.
Above text and translation is from – “http://prabhupadabooks.com/bg”
Looking at Arjuna, who was full of tears, overcome by sorrow, depressed, lamenting, Madhusudhana said these words.
Arjuna and Krishna have been addressed in many names throughout Gita. The names seem to have been addressed according to the context, I presume. Here Madhusudhana means killer of Madhu(Is Madhu = Moha? – I am not really sure about this).
As I heard in one of the discourse by Swami Anubhavananda, Arjuna had no problem killing others(in other wars he fought). But when it was with his own, he had a problem.
So killing was never a problem for Arjuna. He was victorious in many wars. But how can killing somebody not be a sin, whatever be the purpose? May be for a Kshathriya, it is. But lucky him, he had Sri Krishna by his side. But what qualified him to have Krishna by his side?
Arjuna had his flaws. He was arrogant, competitive, jealous, insecure(from what he did to Ekalavya and Karna). But again what qualified him to have Krishna by his side? Devotion? So is Devotion enough to have God by your side?