Bg 2.8

na hi prapasyami mamapanudyad
yac chokam ucchosanam indriyanam
avapya bhumav asapatnam rddham
rajyam suranam api cadhipatyam

Word for word: 
na — do not; hi — certainly; prapasyami — I see; mama — my; apanudyat — can drive away; yat — that which; sokam — lamentation; ucchosanam — drying up; indriyanam — of the senses; avapya — achieving; bhumau — on the earth; asapatnam — without rival; rddham — prosperous; rajyam — kingdom; suranam — of the demigods; api — even; ca — also; adhipatyam — supremacy.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
I can find no means to drive away this grief which is drying up my senses. I will not be able to dispel it even if I win a prosperous, unrivaled kingdom on earth with sovereignty like the demigods in heaven.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Although Arjuna was putting forward so many arguments based on knowledge of the principles of religion and moral codes, it appears that he was unable to solve his real problem without the help of the spiritual master, Lord Sri Krishna. He could understand that his so-called knowledge was useless in driving away his problems, which were drying up his whole existence; and it was impossible for him to solve such perplexities without the help of a spiritual master like Lord Krishna. Academic knowledge, scholarship, high position, etc., are all useless in solving the problems of life; help can be given only by a spiritual master like Krishna. Therefore, the conclusion is that a spiritual master who is one hundred percent Krishna conscious is the bona fide spiritual master, for he can solve the problems of life. Lord Caitanya said that one who is a master in the science of Krishna consciousness, regardless of his social position, is the real spiritual master.

kiba vipra, kiba nyasi, sudra kene naya
yei Krishna-tattva-vetta, sei ‘guru’ haya

“It does not matter whether a person is a vipra [learned scholar in Vedic wisdom], or is born in a lower family, or is in the renounced order of life – if he is a master in the science of Krishna, he is the perfect and bona fide spiritual master.” (Caitanya-caritamrta, Madhya 8.128) So without being a master in the science of Krishna consciousness, no one is a bona fide spiritual master. It is also said in the Vedic literature:

sat-karma-nipuno vipro
mantra-tantra-visaradah
avaisnavo gurur na syad
vaisnavah sva-paco guruh

“A scholarly brahmana, expert in all subjects of Vedic knowledge, is unfit to become a spiritual master without being a Vaisnava, or expert in the science of Krishna consciousness. But a person born in a family of a lower caste can become a spiritual master if he is a Vaisnava, or Krishna conscious.” (Padma Purana)

The problems of material existence – birth, old age, disease and death – cannot be counteracted by accumulation of wealth and economic development. In many parts of the world there are states which are replete with all facilities of life, which are full of wealth and economically developed, yet the problems of material existence are still present. They are seeking peace in different ways, but they can achieve real happiness only if they consult Krishna, or the Bhagavad-gita and Srimad-Bhagavatam – which constitute the science of Krishna – through the bona fide representative of Krishna, the man in Krishna consciousness.

If economic development and material comforts could drive away one’s lamentations for family, social, national or international inebrieties, then Arjuna would not have said that even an unrivaled kingdom on earth or supremacy like that of the demigods in the heavenly planets would be unable to drive away his lamentations. He sought, therefore, refuge in Krishna consciousness, and that is the right path for peace and harmony. Economic development or supremacy over the world can be finished at any moment by the cataclysms of material nature. Even elevation into a higher planetary situation, as men are now seeking on the moon planet, can also be finished at one stroke. The Bhagavad-gita confirms this: ksine punye martya-lokam visanti. “When the results of pious activities are finished, one falls down again from the peak of happiness to the lowest status of life.” Many politicians of the world have fallen down in that way. Such downfalls only constitute more causes for lamentation.

Therefore, if we want to curb lamentation for good, then we have to take shelter of Krishna, as Arjuna is seeking to do. So Arjuna asked Krishna to solve his problem definitely, and that is the way of Krishna consciousness.