indriyāṇāḿ hi caratāḿ
yan mano 'nuvidhīyate
tad asya harati prajñāḿ
vāyur nāvam ivāmbhasi
indriyāṇām — of the senses; hi — certainly; caratām — while roaming; yat — with which; manaḥ — the mind; anuvidhīyate — becomes constantly engaged; tat — that; asya — his; harati — takes away; prajñām — intelligence; vāyuḥ — wind; nāvam — a boat; iva — like; ambhasi — on the water.
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 Ambarisha, all of the senses must be engaged in Krishna consciousness, for that is the correct technique for controlling the mind.