And because in the days of yore Ganga sat on his lap, she, like Urvashi, came to be regarded as his daughter and was named after him. Then having become the kings daughter, she became his son (i.e. she procured, like a son, the salvation of his ancestors).
तथा भागीरथी गङ्गा उर्वशी चाभवत् पुरा। दुहितृत्वं गता राज्ञः पुत्रत्वमगमत् तदा॥