Bhagavad Gita 14.18

ऊर्ध्वं गच्छन्ति सत्त्वस्था मध्ये तिष्ठन्ति राजसाः।जघन्यगुणवृत्तिस्था अधो गच्छन्ति तामसाः॥

ūrdhvaṃ gacchanti sattvasthā madhye tiṣṭhanti rājasāḥ |jaghanyaguṇavṛttisthā adho gacchanti tāmasāḥ ||

Those seated in Sattva ascend; those of Rajasic nature dwell in the middle; and those of Tamasic nature, abiding in the function of the lowest Guna, descend.

When purity is in the ascendant, the man evolves; when passion is in the ascendant, he neither evolves nor degenerates; when ignorance is in the ascendant, he is lost.

Our plain-language meaning of this verse is waiting for scholar review.