Srimad Bhagavatam Canto 07, Chapter 13, Text 27

SB 7.13.27

sukham asyatmano rupam
 sarvehoparatis tanuh
manah-samsparsajan drstva
 bhogan svapsyami samvisan
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
The actual form of life for the living entities is one of spiritual happiness, which is real happiness. This happiness can be achieved only when one stops all materialistic activities. Material sense enjoyment is simply an imagination. Therefore, considering this subject matter, I have ceased from all material activities and am lying down here.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
The difference between the philosophy of the Mayavadis and that of the Vaisnavas is explained herein. Both the Mayavadis and Vaisnavas know that in materialistic activities there is no happiness. The Mayavadi philosophers, therefore, adhering to the slogan brahma satyam jagan mithya, want to refrain from false, materialistic activities. They want to stop all activities and merge in the Supreme Brahman. According to the Vaisnava philosophy, however, if one simply ceases from materialistic activity one cannot remain inactive for very long, and therefore everyone should engage himself in spiritual activities, which will solve the problem of suffering in this material world. It is said, therefore, that although the Mayavadi philosophers strive to refrain from materialistic activities and merge in Brahman, and although they may actually merge in the Brahman existence, for want of activity they fall down again into materialistic activity (aruhya krcchrena param padam tatah patanty adhah). Thus the so-called renouncer, unable to remain in meditation upon Brahman, returns to materialistic activities by opening hospitals and schools and so on. Therefore, simply cultivating knowledge that materialistic activities cannot give one happiness, and that one should consequently cease from such activities, is insufficient. One should cease from materialistic activities and take up spiritual activities. Then the solution to the problem will be achieved. Spiritual activities are activities performed according to the order of Krsna (anukulyena krsnanusilanam). If one does whatever Krsna says, his activities are not material. For example, when Arjuna fought in response to the order of Krsna, his activities were not material. Fighting for sense gratification is a materialistic activity, but fighting by the order of Krsna is spiritual. By spiritual activities one becomes eligible to go back home, back to Godhead, and then enjoy blissful life eternally. Here, in the material world, everything is but a mental concoction that will never give us real happiness. The practical solution, therefore, is to cease from materialistic activities and engage in spiritual activities. Yajñarthat karmano ’nyatra loko ’yam karma-bandhanah). If one works for the sake of pleasing the Supreme Lord — Yajña, or Visnu — one is in liberated life. If one fails to do so, however, he remains in a life of bondage.
Srimad Bhagavatam Canto 07, Chapter 13, Text 26
Srimad Bhagavatam Canto 07, Chapter 13, Text 28