Mahabharata 8.28.44

तं तथा हीयमानं च हंसो दृष्ट्वाब्रवीदिदम्उज्जिहीर्षुर्निमज्जन्तं स्मरन्सत्पुरुषव्रतम्

taṃ tathā hīyamānaṃ ca haṃso dṛṣṭvābravīdidamujjihīrṣurnimajjantaṃ smaransatpuruṣavratam

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