Balarama understood that all these boys and calves were only expansions of Krsna

Expressions researched:
"Balarāma understood that all these boys and calves were only expansions of Kṛṣṇa"

Srimad-Bhagavatam

SB Canto 10.1 to 10.13

He thus concluded that the mystical change must have been caused by Kṛṣṇa, whom Balarāma considered His worshipable Personality of Godhead. He thought, "It was arranged by Kṛṣṇa, and even I could not check its mystic power." Thus Balarāma understood that all these boys and calves were only expansions of Kṛṣṇa.

SB 10.13.37, Translation and Purport

Who is this mystic power, and where has she come from? Is she a demigod or a demoness? She must be the illusory energy of My master, Lord Kṛṣṇa, for who else can bewilder Me?

Balarāma was surprised. This extraordinary show of affection, He thought, was something mystical, performed either by the demigods or some wonderful man. Otherwise, how could this wonderful change take place? "This māyā might be some rākṣasī-māyā," He thought, "but how can rākṣasī-māyā have any influence upon Me? This is not possible. Therefore it must be the māyā of Kṛṣṇa." He thus concluded that the mystical change must have been caused by Kṛṣṇa, whom Balarāma considered His worshipable Personality of Godhead. He thought, "It was arranged by Kṛṣṇa, and even I could not check its mystic power." Thus Balarāma understood that all these boys and calves were only expansions of Kṛṣṇa.