O people of the world! Please try to translate the Gita’s message into action and channel your thoughts toward Lord Krishna’s lotus feet. Serve Him with your mind and body. If you dovetail all your energy in the Lord’s service, then not only will you feel intense exhilaration in this lifetime, but you will be immersed in eternal bliss in the spiritual world, perpetually serving Him.
His Divine Grace A. C. Bhaktivedanta Swami Prabhupada
Renunciation Through Wisdom, Chapter Two

The Supreme Lord is situated in everyone’s heart, O Arjuna, and is directing the wanderings of all living entities, who are seated as on a machine, made of the material energy. O scion of Bharata, surrender unto Him utterly. By His grace you will attain transcendental peace and the supreme and eternal abode.
Lord Sri Krishna
Bhagavad-gita 18.61–62

O best among the brahmanas [Narada], in the previous ages, beginning with Satya, the constant kirtana of harinama was the goal to be attained by austerities and other practices. In the age of Kali, however, such constant kirtana is both the means and the goal.
Lord Shiva
Satvata-tantra 5.48

Perfection in self-realization cannot be attained by any kind of yogi unless he engages in devotional service to the Supreme Personality of Godhead, for that is the only auspicious path.
Lord Kapila
Srimad-Bhagavatam 3.25.19

O Lord, is Your impersonal spiritual effulgence not always present everywhere? Even so, it has not been able to break even a single small leaf from the tree of repeated birth and death. On the other hand, the moment Your holy name is taken by the tongue it thoroughly shatters the tree of birth and death down to its roots. Of these two [the spiritual effulgence or the holy name], which should be served?
Sri Sridhara Swami
Srila Rupa Goswami’s Padyavali 28

Any person who engages himself within this material world in performing activities that necessitate great struggle, and who, after obtaining a human form of life – which is a chance to attain liberation from miseries – undertakes the difficult tasks of fruitive activities, must be considered to be cheated and envious of his own self.
Wives of the Demigods
Srimad-Bhagavatam 4.23.28

The Supreme Personality of Godhead is the source of genuine happiness. Nothing else can bring one actual happiness. Only the Supreme Personality of Godhead can bring one happiness. For this reason one should inquire about the Supreme Personality of Godhead.
Chandogya Upanishad 7.25.1