It is the "odd" [i.e., odd-numbered, Witr] by which Allah swore in the ayah (interpretation of the meaning):
म उनीहरूलाई जिस्क्याउने गर्थेँ — सूर्यनाथले ‘अल्लाह कसम’ भन्छन् र इसुफदिनले ‘रामको कसम’ खान्छन् भनेर ।