Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 37

Sanskrit:

असाध्विदं त्वया कृष्ण कृतमस्मज्जुगुप्सितम् ।वपनं श्मश्रुकेशानां वैरूप्यं सुहृदो वध: ॥ ३७ ॥

ITRANS:

asādhv idaṁ tvayā kṛṣṇakṛtam asmaj-jugupsitamvapanaṁ śmaśru-keśānāṁvairūpyaṁ suhṛdo vadhaḥ

Translation:

[Lord Balarāma said:] My dear Kṛṣṇa, You have acted improperly! This deed will bring shame on Us, for to disfigure a close relative by shaving off his mustache and hair is as good as killing him.

Purport:

Omniscient Balarāma knew that Rukmī was the guilty party, but to encourage the lamenting Rukmiṇī He decided to gently reproach Śrī Kṛṣṇa