Srimad Bhagavatam Canto 11, Chapter 23, Text 60

SB 11.23.60

tasmat sarvatmana tata
 nigrhana mano dhiya
mayy avesitaya yukta
 etavan yoga-sangrahah
 
Translation: 
 
My dear Uddhava, fixing your intelligence on Me, you should thus completely control the mind. This is the essence of the science of yoga.
 
Srimad Bhagavatam Canto 11, Chapter 23, Text 59
Srimad Bhagavatam Canto 11, Chapter 23, Text 61