Mahabharata 12.271.9

नैष दानवता शक्यस्तपसा नैव चेज्ययासंप्राप्तुमिन्द्रियाणां तु संयमेनैव शक्यते

naiṣa dānavatā śakyastapasā naiva cejyayāsaṃprāptumindriyāṇāṃ tu saṃyamenaiva śakyate

Our plain-language meaning of this verse is waiting for scholar review.