Matsyapurana 46.7

46.7

atha sakhyena vṛddhe 'sau kuntibhoje sutāṃ dadau
evaṃ kuntī samākhyātā vasudevasvasā pṛthā //

After that Śûra, out of friendship, gave his daughter, Pṛithâ, for being adopted by Kuntibhoja, who was very old, and for that reason she also came to be known as Kuntî, the sister of Vasudeva. Vasudeva gave in marriage his sister, Kuntî, to King Pâṇḍu, for whom he bore several brave sons, through Devas.—7-8.