This verse from the Bhagavad Gita emphasizes the concept of selfless action (karma yoga) as a means to attain spiritual purity and liberation. Lord Krishna teaches that yogis, those who have mastered the science of yoga, engage in actions using only their body, mind, intellect, and senses, without attachment to the fruits of their actions.

Firstly, Krishna mentions "kāyena," which refers to actions performed with the body. Yogis engage in righteous deeds and service to others, using their physical capabilities for the welfare of society and without seeking personal gain or recognition.

Secondly, Krishna speaks of actions performed "manasā," with the mind. This indicates that yogis cultivate mental discipline and focus, directing their thoughts and intentions towards higher ideals and spiritual growth. They maintain a positive attitude and inner peace, regardless of external circumstances.

Thirdly, Krishna mentions "buddhyā," actions performed with the intellect. Yogis make decisions based on wisdom and discernment, guided by their understanding of dharma (righteous duty) and the teachings of scriptures. They use their intelligence to discern between right and wrong and to choose actions that align with their spiritual goals.

Lastly, Krishna refers to actions performed "kevalair indriyair api," with the senses alone. Yogis maintain control over their senses, not allowing them to be swayed by external stimuli or desires. They restrain from indulging in sensory pleasures that lead to attachment and instead use their senses in the service of higher ideals and spiritual pursuits.

By performing actions in this selfless manner, yogis renounce attachment to the results of their actions (saṅgaṁ tyaktvā) and focus on self-purification (ātmaśhuddhaye). They understand that true fulfillment and liberation come from detaching oneself from the ego and identifying with the eternal soul (ātman). Thus, through the practice of karma yoga, yogis attain spiritual growth, inner purity, and ultimately, liberation from the cycle of birth and death.