Shloka 18
उशनसः (शुक्रस्य) चरितम् — The Account of Uśanā (Śukra): Yoga, Grievance, and Pacification
क्षपयित्वा तु तं कालं गणितं कालचोदिता: । सावशेषेण कालेन सम्भवन्ति पुन: पुन:
kṣapayitvā tu taṃ kālaṃ gaṇitaṃ kālacoditāḥ | sāvaśeṣeṇa kālena sambhavanti punaḥ punaḥ ||
ビーシュマは言った。定められ、数え定められたその時分を尽くすと――時（カーラ）そのものに促され――なお受けるべき業の残りがあるかぎり、彼らは幾度も幾度も生まれ変わる。ゆえに、天界や地獄で定めの期間だけ業果を味わった後でさえ、残余の業が尽きるまで衆生は世間の存在へと帰って来るのである。
भीष्म उवाच
Educational Q&A
Even after a being enjoys or suffers the results of actions in heaven or hell for a fixed duration, rebirth continues until the remaining (residual) karma is exhausted; Time (kāla) is presented as the force that propels this recurring cycle.
In Bhīṣma’s instruction to Yudhiṣṭhira in the Śānti Parva, he explains the mechanics of post-mortem experience and return: beings spend the allotted term for their karmic fruits, and then—if any karmic residue remains—Time drives them back into repeated births in the world.