Bhagavān reveals in the following verses of the Srīmad Bhagavadgītā. the path taken by one who seeks liberation.
बुद्ध्या विशुद्धया युक्तो धृत्यात्मानं नियम्य च ।
शब्दादीन्विषयांस्त्यक्त्वा रागद्वेषौ व्युदस्य च ॥ १८-५१॥
The one endowed with purified intellect, holding himself in steadfast discipline, disconnecting himself from sound and other sense inputs, and having forsaken the feelings of attraction and repulsion...
विविक्तसेवी लघ्वाशी यतवाक्कायमानसः ।
ध्यानयोगपरो नित्यं वैराग्यं समुपाश्रितः ॥ १८-५२॥
Being in solitude, eating meagerly just to keep the body and soul together, disciplining his thought, word, and deed, and engaged in meditation constantly, and establishing himself in dispassion...
अहङ्कारं बलं दर्पं कामं क्रोधं परिग्रहम् ।
विमुच्य निर्ममः शान्तो ब्रह्मभूयाय कल्पते ॥ १८-५३॥
Eschewing ego, power, arrogance, desires, anger, and attachments to his own possessions, he gives up the sense of "I and mine" and becomes peaceful. And then, he attains the experience of Brahman.
What is there anymore for such a man?
Indeed, this is where the next stage begins!
ब्रह्मभूतः प्रसन्नात्मा न शोचति न काङ्क्षति ।
समः सर्वेषु भूतेषु मद्भक्तिं लभते पराम् ॥ १८-५४॥
The sign of such a man established in Brahman is his cheerfulness. He never grieves and never desires. He is equal towards all creation, all beings, and develops devotion to Bhagavān. "Madbhaktim labhate parām", "He attains supreme devotion to me", says Bhagavān.
भक्त्या मामभिजानाति यावान्यश्चास्मि तत्त्वतः ।
ततो मां तत्त्वतो ज्ञात्वा विशते तदनन्तरम् ॥ १८-५५॥
सर्वकर्माण्यपि सदा कुर्वाणो मद्व्यपाश्रयः ।
मत्प्रसादादवाप्नोति शाश्वतं पदमव्ययम् ॥ १८-५६॥
Through devotion he gets a complete and perfect understanding of me ( that is, Bhagavān). Having known me thus, he enters into me. He then does all his actions in this world - his actions do not stop but continue - but he performs all his actions being established in me. Through my grace (i.e. through Bhagavān's prasāda), he attains a state of permanent immersion in divinity.
Thus, the summum bonum of the spiritual path is perfect devotion in action, according to the Srīmad Bhagavadgītā.
