One verse

Srimad Bhagavatam 9.16.33

9.16.33

ये मधुच्छन्दसो ज्येष्ठा: कुशलं मेनिरे न तत् । अशपत् तान्मुनि: क्रुद्धो म्‍लेच्छा भवत दुर्जना: ॥ ३३ ॥

ye madhucchandaso jyesthah kusalam menire na tat asapat tan munih kruddho mleccha bhavata durjanah

ye
those who
madhucchandasah
sons of Visvamitra, celebrated as the Madhucchandas
jyesthah
eldest
kusalam
very good
menire
accepting
na
not
tat
that (the proposal that he be accepted as the eldest brother)
asapat
cursed
tan
all the sons
munih
Visvamitra Muni
kruddhah
being angry
mlecchah
disobedient to the Vedic principles
bhavata
all of you become
durjanah
very bad sons.

When requested by their father to accept Sunahsepha as the eldest son, the elder fifty of the Madhucchandas, the sons of Visvamitra, did not agree. Therefore Visvamitra, being angry, cursed them May all of you bad sons become mlecchas he said, being opposed to the principles of Vedic culture