Srimad Bhagavatam Canto 06, Chapter 19, Text 11

SB 6.19.11

yuvam tu visvasya vibhu
 jagatah karanam param
iyam hi prakrtih suksma
 maya-saktir duratyaya
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
My Lord Visnu and mother Laksmi, goddess of fortune, you are the proprietors of the entire creation. Indeed, you are the cause of the creation. Mother Laksmi is extremely difficult to understand because she is so powerful that the jurisdiction of her power is difficult to overcome. Mother Laksmi is represented in the material world as the external energy, but actually she is always the internal energy of the Lord.
Srimad Bhagavatam Canto 06, Chapter 19, Text 10
Srimad Bhagavatam Canto 06, Chapter 19, Text 12