Srimad Bhagavatam Canto 08, Chapter 01, Text 14

SB 8.1.14

athagre rsayah karman-
 ihante ’karma-hetave
ihamano hi purusah
 prayo ’niham prapadyate
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Therefore, to enable people to reach the stage of activities that are not tinged by fruitive results, great saints first engage people in fruitive activities, for unless one begins by performing activities as recommended in the sastras, one cannot reach the stage of liberation, or activities that produce no reactions.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
In Bhagavad-gita (3.9) Lord Krsna advises, yajñarthat karmano ’nyatra loko ’yam karma-bandhanah: “Work done as a sacrifice for Visnu has to be performed; otherwise work binds one to this material world.” Generally, everyone is attracted to hard labor for becoming happy in this material world, but although various activities are going on all over the world simply for the sake of happiness, unfortunately only problems are being created from such fruitive activities. Therefore it is advised that active persons engage in activities of Krsna consciousness, which are called yajña, because then they will gradually come to the platform of devotional service. Yajña means Lord Visnu, the yajña-purusa, the enjoyer of all sacrifices (bhoktaram yajña-tapasam sarva-loka-mahesvaram). The Supreme Personality of Godhead is actually the enjoyer, and therefore if we begin our activities for His satisfaction, we will gradually lose our taste for material activities.
Suta Gosvami declared to the great assembly of sages at Naimisaranya:
atah pumbhir dvija-srestha
svanusthitasya dharmasya
 samsiddhir hari-tosanam
“O best among the twice-born, it is concluded that the highest perfection one can achieve, by discharging his prescribed duties [dharma] according to caste divisions and order of life, is to please the Lord Hari.” (Bhag. 1.2.13) According to Vedic principles, everyone must act according to his classification as brahmana, ksatriya, vaisya, sudra, brahmacari, grhastha, vanaprastha or sannyasi. Everyone should progress toward perfection by acting in such a way that Krsna will be pleased (samsiddhir hari-tosanam). One cannot please Krsna by sitting idly; one must act according to the directions of the spiritual master for the sake of pleasing the Supreme Personality of Godhead, and then one will gradually come to the stage of pure devotional service. As confirmed in Srimad-Bhagavatam (1.5.12):
naiskarmyam apy acyuta-bhava-varjitam
 na sobhate jñanam alam nirañjanam
“Knowledge of self-realization, even though freed from all material affinity, does not look well if devoid of a conception of the infallible [God].” Jñanis recommend that one adopt naiskarmya by not doing anything but simply meditating and thinking of Brahman, but this is impossible unless one realizes Parabrahman, Krsna. If there is no Krsna consciousness, any kind of activity, be it philanthropic, political or social, simply causes karma-bandhana, bondage to material work.
As long as one is entangled in karma-bandhana, one must accept different types of bodies that spoil the human form of facility. Therefore, in Bhagavad-gita (6.3) karma-yoga is recommended:
aruruksor muner yogam
 karma karanam ucyate
yogarudhasya tasyaiva
 samah karanam ucyate
“For one who is a neophyte in the yoga system, work is said to be the means; and for one who has already attained to yoga, cessation of all material activities is said to be the means.” Nonetheless:
karmendriyani samyamya
 ya aste manasa smaran
indriyarthan vimudhatma
 mithyacarah sa ucyate
“One who restrains the senses and organs of action, but whose mind dwells on sense objects, certainly deludes himself and is called a pretender.” (Bg. 3.6) One should act for Krsna very seriously in order to become fully Krsna conscious and should not sit down to imitate such great personalities as Haridasa Thakura. Srila Bhaktisiddhanta Sarasvati Thakura condemned such imitation. He said:
dusta mana! tumi kisera vaisnava?
pratisthara tare, nirjanera ghare,
tava hari-nama kevala kaitava
“My dear mind, what kind of devotee are you? Simply for cheap adoration, you sit in a solitary place and pretend to chant the Hare Krsna maha-mantra, but this is all cheating.” Recently at Mayapur an African devotee wanted to imitate Haridasa Thakura, but after fifteen days he became restless and went away. Do not suddenly try to imitate Haridasa Thakura. Engage yourself in Krsna conscious activities, and gradually you will come to the stage of liberation (muktir hitvanyatha rupam svarupena vyavasthitih).
Srimad Bhagavatam Canto 08, Chapter 01, Text 13
Srimad Bhagavatam Canto 08, Chapter 01, Text 15