Chap 2, Shloka 66 - 67

Shloka 66 and 67.
Translations from Shri Prabhupada's "Bhagavad Gita As it is"

Shloka 66
http://www.asitis.com/2/66.html

nasti buddhir ayuktasya na cayuktasya bhavana
na cabhavayatah santir asantasya kutah sukham


SYNONYMS
na asti--there cannot be; buddhih--transcendental intelligence; ayuktasya--of one who is not connected (with Krsna consciousness); na--neither; ca--and; ayuktasya--of one devoid of Krsna consciousness; bhavana--mind fixed in happiness; na--neither; ca--and; abhavayatah--one who is not fixed; santih--peace; asantasya--of the unpeaceful; kutah--where is; sukham--happiness.

TRANSLATION
One who is not in transcendental consciousness can have neither a controlled mind nor steady intelligence, without which there is no possibility of peace. And how can there be any happiness without peace?

PURPORT
Unless one is in Krsna consciousness there is no possibility of peace. So it is confirmed in the Fifth Chapter (5.29) that when one understands that Krsna is the only enjoyer of all the good results of sacrifice and penance, and that He is the proprietor of all universal manifestations, that He is the real friend of all living entities, then only can one have real peace. Therefore, if one is not in Krsna consciousness, there cannot be a final goal for the mind. Disturbance is due to want of an ultimate goal, and when one is certain that Krsna is the enjoyer, proprietor and friend of everyone and everything, then one can, with a steady mind, bring about peace. Therefore, one who is engaged without a relationship with Krsna is certainly always in distress and is without peace, however much he may make a show of peace and spiritual advancement in life. Krsna consciousness is a self-manifested peaceful condition which can be achieved only in relationship with Krsna.


Shloka 67
http://www.asitis.com/2/67.html

indriyanam hi caratam yan mano 'nuvidhiyate
tad asya harati prajnam vayur navam ivambhasi


SYNONYMS
indriyanam--of the senses; hi--certainly; caratam--while herding over; yat--that; manah--mind; anuvidhiyate--becomes constantly engaged; tat--that; asya--his; harati--takes away; prajnam--intelligence; vayuh--wind; navam--a boat; iva--like; ambhasi--on the water.

TRANSLATION
As a boat on the water is swept away by a strong wind, even one of the senses on which the mind focuses can carry away a man's intelligence.


PURPORT
Unless all of the senses are engaged in the service of the Lord, even one of them engaged in sense gratification can deviate the devotee from the path of transcendental advancement. As mentioned in the life of Maharaja Ambarisa, all of the senses must be engaged in Krsna consciousness, for that is the correct technique for controlling the mind.