Matsya Purana 226.9

226.9

yathā sarvāṇi bhūtāni bibhrataḥ pārthivaṃ vratam.
indrasyārkasya vātasya yamasya varuṇasya ca .. 226.8 ..

He should always observe this Âgneya vrata. As the earth holds up all the beings, so a king nourishes all his subjects. This is his Pârthivavrata. As all the subjects of a sovereign are steady in their devotion to him, so is he in his devotion to Indra, Sûrya, Vâyu, Yama, Varuṇa, Chandramâ, Agni and Pṛithvî. He sustains his subjects as Indra pours forth rain for four months during the rains. This is Indra vrata. He takes revenues from his subjects as the Sun draws in moisture by his rays for eight months. This is Sûryavrata.—8-10.