SB 4.29.7
brhad-balam mano vidyad
ubhayendriya-nayakam
pañcalah pañca visaya
yan-madhye nava-kham puram
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The eleventh attendant, who is the commander of the others, is known as the mind. He is the leader of the senses both in the acquisition of knowledge and in the performance of work. The Pañcala kingdom is that atmosphere in which the five sense objects are enjoyed. Within that Pañcala kingdom is the city of the body, which has nine gates.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The mind is the center of all activities and is described here as brhad-bala, very powerful. To get out of the clutches of maya, material existence, one has to control his mind. According to training, the mind is the friend and the enemy of the living entity. If one gets a good manager, his estate is very nicely managed, but if the manager is a thief, his estate is spoiled. Similarly, in his material, conditional existence, the living entity gives power of attorney to his mind. As such, he is liable to be misdirected by his mind into enjoying sense objects. Srila Ambarisa Maharaja therefore first engaged his mind upon the lotus feet of the Lord (sa vai manah krsna-padaravindayoh). When the mind is engaged in meditation on the lotus feet of the Lord, the senses are controlled. This system of control is called yama, and this means “subduing the senses.” One who can subdue the senses is called a gosvami, but one who cannot control the mind is called go-dasa. The mind directs the activities of the senses, which are expressed through different outlets, as described in the next verse.