Mahabharata 6.63.16

ब्रह्मभूतममावास्यां पौर्णमास्यां तथैव चयोगभूतं परिचरन्केशवं महदाप्नुयात्

brahmabhūtamamāvāsyāṃ paurṇamāsyāṃ tathaiva cayogabhūtaṃ paricarankeśavaṃ mahadāpnuyāt

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