Chapter 3, Verse 41
tasmāt-tvam-indriyāṇyādau
niyamya bharatarṣabha
pāpmānaṁ prajahi hyenaṁ
jñāna vijñāna nāśanam
Therefore, O Arjuna, controlling the senses first, slay desire, this deluding thing that destroys both knowledge and discrimination.
Lord Krishna says, “First control the senses: they are easier to control, because they are outside. Control too much sleep. Control what you are eating. Control what you are doing in your actions. Control the mind. Don’t let the mind dwell on the attraction of worldly perishable things, which will bring you sorrow.” Use all the senses, transforming them by serving God, by hearing His glory, by chanting and by concentrating on the Divine Names, on the different Names of God. Use the hands, the touch, to serve God through the action. Like that, you don’t go into the game of worldly enjoyments. Keep yourself busy with the right things. If you start running after these desires, if you entertain them in the mind, it will destroy knowledge and discrimination. It will destroy everything good inside of you. People without discrimination really can’t think. Even if you tell them something good, it doesn’t have any effect on them.
Jñāna vijñāna nāśanam. Desire destroys the power of discrimination. It destroys the greater knowledge inside, the knowledge of the Divine. It is through this knowledge that the Divine acts inside people. If this knowledge is veiled, then life will be very difficult, because one will not be guided by knowledge and discrimination. One will always feel self-pity and sadness. Krishna says to Arjuna, “Be knowledgeable about the Self! Have the power to discriminate! Because, if you have knowledge and the power to discriminate, desire has no power.” You can uproot desire itself and transform it. Ignorance will be eradicated in the presence of knowledge and discrimination. When there is knowledge and discrimination, then one has a pacified mind, a calm mind, which is focused on the Divine.
Bhagavad Gita