CC Ādi 13.52

kona vāñchā pūraṇa lāgi’ vrajendra-kumāra
avatīrṇa haite mane karilā vicāra
Synonyms: 
kona — some; vāñchā — desire; pūraṇa — fulfillment; lāgi’ — for the matter of; vrajendra-kumāra — Lord Kṛṣṇa; avatīrṇa haite — to descend as an incarnation; mane — in the mind; karilā — did; vicāra — consideration.
Translation: 
To fulfill a particular desire within His mind, Lord Kṛṣṇa, Vrajendra-kumāra, decided to descend to this planet after mature contemplation.