Caitanya-caritāmṛta 3.93
kṛṣṇa yadi pṛthivīte karena avatāra prathame karena guru-vargera sañcāra
[krishna yadi prithiveete karena avataara prathame karena guru-vargera sanchaara]
Blended reading (Sanskrit + English inline)
kṛṣṇa yadi pṛthivīte karena avatāra prathame karena guru-vargera sañcāra
Whenever Śrī Kṛṣṇa desires to manifest His incarnation on earth, first He creates the incarnations of His respectable predecessors.
My note
Source: vedabase.io