Talk 45, Ch 4, Ma 10-11, Svetaswatara Upanishad

Know then that Nature is Maya, and that the great God is the Lord of Maya. The whole world is filled with beings who form His parts.
One attains infinite peace on understanding that self-effulgent Adorable Lord, the bestower of blessings, who, though one, presides over all the various aspects of Prajapati, and in whom this universe dissolves, and in whom it appears in manifold forms.