Mahabharata 7.56.8

7.56.8

putraśokābhibhūtena pratijñāto mahātmanā |
sahasā sindhurājasya vadho gāṇḍīvadhanvanā || 8 ||

Wakefulness possessed every one, O monarch. And everybody (in the Pandava camp) thought of this, viz.,--The high-souled wielder of Gandiva, burning with grief for the death of his son, hath suddenly vowed the slaughter of the Sindhus. How, indeed, will that slayer of hostile heroes, that son of Vasava, that mighty-armed warrior, accomplish his vow? The high-souled son of Pandu hath, indeed made a most difficult resolve. King Jayadratha is endued with mighty energy. Oh, let Arjuna succeed in fulfilling his vow. Difficult is that vow which he, afflicted with grief on account of his son, hath made. Duryodhana's brothers are all possessed of great prowess. His forces also are countless. The son of Dhritarashtra hath assigned all these to Jayadratha (as his protectors). Oh, let Dhananjaya come back (to the camp), having slain the ruler of the Sindhus in battle. Vanquishing his foes, let Arjuna accomplish his vow. If he fails to slay the ruler of the Sindhus tomorrow, he will certainly enter into blazing fire. Dhananjaya, the son of Pritha, will not falsify his oath. If Arjuna dies, how will the son of Dharma succeed in recovering his kingdom? Indeed, (Yudhishthira) the son of Pandu hath reposed (all his hopes of) victory of Arjuna.