Following the will of the S P of Godhead, I create, Lord Siva destroys, and He Himself in the form of Ksirodakasayi Visnu maintains all the affairs of material nature. Thus the supreme controller of the three modes of material nature is Lord Visnu

Expressions researched:
"Following the will of the Supreme Personality of Godhead, I create, Lord Śiva destroys, and He Himself in the form of Kṣīrodakaśāyī Viṣṇu maintains all the affairs of material nature. Thus the supreme controller of the three modes of material nature is Lord Viṣṇu"

Sri Caitanya-caritamrta

CC Madhya-lila

“[Lord Brahmā said:] ‘Following the will of the Supreme Personality of Godhead, I create, Lord Śiva destroys, and He Himself in the form of Kṣīrodakaśāyī Viṣṇu maintains all the affairs of material nature. Thus the supreme controller of the three modes of material nature is Lord Viṣṇu.’

CC Madhya 21.37, Translation and Purport

“[Lord Brahmā said:] ‘Following the will of the Supreme Personality of Godhead, I create, Lord Śiva destroys, and He Himself in the form of Kṣīrodakaśāyī Viṣṇu maintains all the affairs of material nature. Thus the supreme controller of the three modes of material nature is Lord Viṣṇu.’

This is a quotation from Śrīmad-Bhāgavatam (SB 2.6.32).