What is the meaning of "Lord of everything and its Sovereign Master" mentioned in the well-known supplication?

The phrase "Lord of everything and its Sovereign" appears in several hadiths, including the hadith of Abu Bakr al-Siddiq, may Allah be pleased with him, where the Prophet, peace and blessings be upon him, taught him to say it as part of the morning and evening remembrances and before sleeping. Its meaning is: "Lord of everything" means its nurturer and reformer, and "its Sovereign" means its owner.