In the nineteenth and twentieth incarnations, the Lord advented Himself as Lord Balarāma and Lord Kṛṣṇa in the family of Vṛṣṇi [the Yadu dynasty], and by so doing He removed the burden of the world.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
एकोनविंशे विंशतिमे वृष्णिषु प्राप्य जन्मनी । रामकृष्णाविति भुवो भगवानहरद्भरम्
ekonaviṃśe viṃśatime vṛṣṇiṣu prāpya janmanī | rāmakṛṣṇāviti bhuvo bhagavānaharadbharam
SB 1.3.23