Bhagavad Gita: Chapter 6, Verse 28

युञ्जन्नेवं सदात्मानं योगी विगतकल्मष: |
सुखेन ब्रह्मसंस्पर्शमत्यन्तं सुखमश्नुते || 28||

yuñjann evaṁ sadātmānaṁ yogī vigata-kalmaṣhaḥ
sukhena brahma-sansparśham atyantaṁ sukham aśhnute

yuñjanuniting (the self with God); evamthus; sadāalways; ātmānamthe self; yogīa yogi; vigatafree from; kalmaṣhaḥsins; sukhenaeasily; brahma-sansparśhamconstantly in touch with the Supreme; atyantamthe highest; sukhambliss; aśhnuteattains

yunjann evam sadatmanam yogi vigata-kalmashah
sukhena brahma-sansparsham atyantam sukham ashnute


BG 6.28: The self-controlled yogi, thus uniting the self with God, becomes free from material contamination, and being in constant touch with the Supreme, achieves the highest state of perfect happiness.


Happiness can be classified into four categories:

sāttvikaṁ sukhamātmotthaṁ viṣhayotthaṁ tu rājasam
tāmasaṁ moha dainyotthaṁ nirguṇaṁ madapāśhrayām
(Bhāgavatam 11.25.29)[v21]

Tāmasic happiness. This is the pleasure derived from narcotics, alcohol, cigarettes, meat products, violence, sleep, etc.

Rājasic happiness. This is the pleasure from the gratification of the five senses and the mind.

Sāttvic happiness. This is the pleasure experienced through practicing virtues, such as compassion, service to others, cultivation of knowledge, stilling of the mind, etc. It includes the bliss of self-realization experienced by the jñānīs when they stabilize the mind upon the soul.

Nirguṇa happiness. This is the divine bliss of God, which is infinite in extent. Shree Krishna explains that the yogi who becomes free from material contamination and becomes united with God attains this highest state of perfect happiness. He has called this unlimited bliss in verse 5.21 and supreme bliss in verse 6.21.