Those who are seated in Sattva go upwards; the Rajasic dwell in the middle; and the Tamasic, abiding in the function of the lowest Guna, go downwards.
In simple words
Krishna describes the trajectories: "People rooted in purity rise upward. People rooted in passion stay in the middle. People rooted in inertia sink downward."
Word-by-word meanings
ऊर्ध्वम्upwardsगच्छन्तिgoसत्त्वस्थाःin Sattva seatedमध्येin the middleतिष्ठन्तिdwellराजसाःthe Rajasicजघन्यगुणवृत्तिस्थाःabiding in the function of the lowest Gunaअधःdownwardsगच्छन्तिgoतामसाःthe Tamasic
Contemporary scholarly and practical interpretations for modern seekers.
Swami Sivananda
14.18 ऊर्ध्वम् upwards? गच्छन्ति go? सत्त्वस्थाः in Sattva seated? मध्ये in the middle? तिष्ठन्ति dwell? राजसाः the Rajasic? जघन्यगुणवृत्तिस्थाः abiding in the function of the lowest Guna? अधः downwards? गच्छन्ति go? तामसाः the Tamasic.Commentary Those who abide in Sattva become the lords of heaven after giving up the physical body. The Rajasic are rorn on this earth as human beings. The Tamasic go downwards? i.e.? they will be born in the wormbs of cattle and beasts. They may take their birth amongst the lowest grades of human beings. The lowest grades of human beings are only brutes though they have assumed human form. Their actions are brutal. Therefore it is not necessary for them to enter into animal incarnation.Man identifies himself with Nature on account of the force of ignorance or illusory knowledge and gets attached to the alities of Nature. This is the cause of his birth in the wombs of high or low creatures. He feels? I am happy? miserable or deluded? on account of the attachment to the Gunas.The nature of the Gunas? their functions? how they bind a man to the Samsara? the effects of each Guna when it is predominant? and the plane reached by the man when he is under the influence of a particular Guna are described in the previous verses. Now the Lord describes in the following verse that liberation comes when one knows Him Who is above the three Gunas.
Swami Chinmayananda
This interpretation draws on a specific tradition and may not represent the view of any single school. For authoritative guidance within a specific tradition, seek a qualified teacher.
The path of evolution has three stages. In the lowest stage of development are the plant and animal kingdoms. Humanity, endowed with intellect and talent, occupies the middle position, and the Vedas reveal that the celestial beings dwell in a state superior to humans. Here, evolution means the vast expanse of experiences and knowledge, the diminishment of mental disturbances, and the sharpness of intellect. The measure of evolution is the degree of happiness, peace, and bliss experienced by living beings. From this perspective, a stone would be considered to have zero evolution. Thereafter follows the ascending order of evolution: plants, animals, humans, and celestial beings. Undoubtedly, the sharp-minded human is a superior being to animals, yet even they are bound by the limitations of space and time. When these limitations are transcended, the human attains the superior state of celestial existence. For example, consider a two-storied building. To reach a room on the second floor, there is a staircase divided into two sections. After climbing several steps in the first section, there is a landing in the middle, from which one must turn and climb the second section of the staircase. Those standing at the very bottom represent the lowest stage of evolution; those standing at the middle landing are in a higher position; and those who have climbed the second section are in the highest state. At the lowest are plants and animals, in the middle is humanity, and in a state superior to that are the celestial beings. Note that none of these three has yet reached the comfortable and well-furnished room. The human, standing in the middle, has the freedom to ascend to a higher state or descend to a lower one. If we understand this illustration well, we may say we have grasped, to some extent, the principle of evolution described in Hindu philosophy. Here, the measure of evolution is the degree of consciousness manifested by each evolved being.
Those established in sattva attain the higher realms. Those who live a pure life of discrimination, reflection, right judgment, and self-restraint experience a progressive increase in sattvic qualities. Such peaceful, creative, and powerful individuals progress toward the higher worlds.
Those of rajasic nature, filled with desire and distraction, ambition and achievement, repeatedly attain the human realm until they acquire the necessary purification of mind.
Living beings who indulge in base tendencies such as negligence, delusion, and ignorance bring about their own downfall.
Even while describing the continuity of the soul's existence after death, Lord Sri Krishna revealed the influence of the three gunas upon the soul's journey. The verse above is a summary of that teaching. But then, where is liberation from the world? Like a rope, these three gunas bind us to the body and its sufferings, to the mind and its disturbances, to the intellect and its fluctuations and limitations. When shall we experience our true nature of existence-consciousness-bliss, freed from this bondage of the world?
Thus far, the nature, characteristics, and influence of the three gunas upon the soul's journey after death have been described. Yet all of this merely describes the causes of our bondage.
The soul dwelling in nature is called the individual being. The experience of the impermanent world, the suffering of disappointments—this is the world of the soul. Liberation can be attained only by transcending the three gunas.
A patient suffering from high fever experiences unbearable pain in the head and back. This pain is a symptom of the disease. Even after the fever subsides, the patient continues to suffer. Only when the person is completely free from all symptoms of that illness and regains health and strength as before can we say they are fully healed. Similarly, true liberation is to transcend all three gunas and become established in one's own blissful nature.
Now, we shall describe how liberation is attained through right understanding.