Yoga Sūtra Chapter Four verse 10
तासामनादित्वं चाशिषो नित्यत्वात् ॥१०॥
tāsām-anāditvaṃ cā-āśisaḥ nityatvāt ||10||
And the beginninglessness of these is due to the eternality of primordial desire.
tāsām - of theseanāditva - beginninglessnessca - andāśis - premordial desirenityatvā - eternality