Chapter 14 · The Three Qualities · Krishna said
Bhagavad Gita 14.18 — Upward, middle, downward
ऊर्ध्वं गच्छन्ति सत्त्वस्था मध्ये तिष्ठन्ति राजसाः। जघन्यगुणवृत्तिस्था अधो गच्छन्ति तामसाः ॥
ūrdhvaṃ gacchanti sattvasthā madhye tiṣṭhanti rājasāḥ | jaghanyaguṇavṛttisthā adho gacchanti tāmasāḥ ||
Meaning
Those established in sattva rise upward, those in rajas stay in the middle, and those in tamas, the lowest quality, go downward.