SB 9.18.2

rājyaṁ naicchad yatiḥ pitrā
 dattaṁ tat-pariṇāmavit
yatra praviṣṭaḥ puruṣa
 ātmānaṁ nāvabudhyate
Synonyms: 
rājyam — the kingdom; na aicchat — did not accept; yatiḥ — the eldest son, Yati; pitrā — by his father; dattam — offered; tat-pariṇāma-vit — knowing the result of becoming powerful as a king; yatra — wherein; praviṣṭaḥ — having entered; puruṣaḥ — such a person; ātmānam — self-realization; na — not; avabudhyate — will take seriously and understand.
Translation: 
When one enters the post of king or head of the government, one cannot understand the meaning of self-realization. Knowing this, Yati, the eldest son of Nahuṣa, did not accept the power to rule, although it was offered by his father.
Purport: 

Self-realization is the prime objective of human civilization, and it is regarded seriously by those who are situated in the mode of goodness and have developed the brahminical qualities. Kṣatriyas are generally endowed with material qualities conducive to gaining material wealth and enjoying sense gratification, but those who are spiritually advanced are not interested in material opulence. Indeed, they accept only the bare necessities for a life of spiritual advancement in self-realization. It is specifically mentioned here that if one enters political life, especially in the modern day, one loses the chance for human perfection. Nonetheless, one can attain the highest perfection if one hears Śrīmad-Bhāgavatam. This hearing is described as nityaṁ bhāgavata-sevayā. Mahārāja Parīkṣit was involved in politics, but because at the end of his life he heard Śrīmad-Bhāgavatam from Śukadeva Gosvāmī, he attained perfection very easily. Śrī Caitanya Mahāprabhu has therefore suggested:

sthāne sthitāḥ śruti-gatāṁ tanu-vāṅ-manobhir
 ye prāyaśo ’jita jito ’py asi tais tri-lokyām

(Bhāg. 10.14.3)

Regardless of whether one is in the mode of passion, ignorance or goodness, if one regularly hears Śrīmad-Bhāgavatam from the self-realized soul, one is freed from the bondage of material involvement.