When a fire, for some unseen reason, leaps over one piece of wood and sets fire to the next, the reason is destiny. Similarly, when a living being accepts one kind of body and leaves aside another, there is no other reason than unseen destiny.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
अग्नेर्यथा दारुवियोगयोगयो- रदृष्टतोऽन्यन्न निमित्तमस्ति । एवं हि जन्तोरपि दुर्विभाव्यः शरीरसंयोगवियोगहेतुः
agneryathā dāruviyogayogayo- radṛṣṭato'nyanna nimittamasti | evaṃ hi jantorapi durvibhāvyaḥ śarīrasaṃyogaviyogahetuḥ
SB 10.1.51