Muṇḍaka Upaniṣad · 3.1.7
यस्त्वविज्ञानवान् भवत्यमनस्कः सदाऽशुचिः । न स तत्पदमाप्नोति संसारं चाधिगच्छति
yas tv avijñānavān bhavaty amanaskaḥ sadā'śuciḥ | na sa tat padam āpnoti saṃsāraṃ cādhigacchati
But whoever is devoid of discrimination, devoid of mind, ever impure — he does not reach that goal, but falls into the cycle of births.
The consequences of lack of control: perpetuation of saṃsāra.
Amanaskaḥ — devoid of mind. Not absence of mind but undisciplined mind, without higher direction.
Sadā aśuciḥ — ever impure. Impurity not moral but of identification with the limited.
Tat padam — that goal. Brahman, liberation, the end of the journey.
Na āpnoti — does not reach. The goal is available but requires appropriate means.
Saṃsāraṃ adhigacchati — falls into the cycle. Birth, death and rebirth continue.
The chariot metaphor illustrates: without a conscious charioteer, the journey is circular, never reaching destination. The chariot keeps turning in the same track of conditioned existences.
The call to practice is urgent: without discipline, there is no exit.