Chapter 13 · The Field and the Knower · Krishna said
Bhagavad Gita 13.22 — Attachment causes rebirth
पुरुषः प्रकृतिस्थो हि भुङ्क्ते प्रकृतिजान्गुणान्। कारणं गुणसङ्गोऽस्य सदसद्योनिजन्मसु ॥
puruṣaḥ prakṛtistho hi bhuṅkte prakṛtijānguṇān | kāraṇaṃ guṇasaṅgo'sya sadasadyonijanmasu ||
Meaning
The Self, dwelling in nature, experiences the qualities born of nature. Its attachment to these qualities is the reason for its birth in good or bad wombs.