Mahabharata 6.81.18

उक्त्वा तथा त्वं पितुरग्रतो मा;महं हनिष्यामि महाव्रतं तम्भीष्मं शरौघैर्विमलार्कवर्णैः; सत्यं वदामीति कृता प्रतिज्ञा

uktvā tathā tvaṃ pituragrato mā;mahaṃ haniṣyāmi mahāvrataṃ tambhīṣmaṃ śaraughairvimalārkavarṇaiḥ; satyaṃ vadāmīti kṛtā pratijñā

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