Do they have to be reborn as a human in one of their remaining seven lives or can they just choose to be reborn in the higher heavenly realms and ascend through them in their remaining lives without coming back to the human world?
Certainly they can be born as devas and never return as humans.
Although it is possible (the texts say:With the ending of three fetters, they have at most seven rebirths. They will transmigrate at most seven times among gods and humans and then make an end of suffering With Residue.)
But I haven’t come across any accounts of a human sotapanna being reborn as a human - the examples I read are always reborn as devas .
Thank you for answering.
What about once-returners? Do they have to return to the human world or can they just be reborn in the deva world and not return to the human world?
I found something interesting from the Sakkapañhasutta and its commentary
It mentions King Sakka’s remaining future lives which includes a human life:
Here is the commentarial explanation:
Amūḷho gabbhamessāmīti niyatagatikattā amūḷho hutvā. Yattha me ramatī manoti yattha me mano ramissati, tattheva khattiyakulādīsu gabbhaṃ upagacchissāmīti sattakkhattuṃ deve ca mānuse cāti imamatthaṃ dīpeti.
“Unconfused I will enter a womb”: because his destination is fixed, he will enter a womb without confusion.
“Where my mind delights”: wherever his mind delights, there he will enter a womb, such as in a noble family. By this he indicates the meaning that he will be reborn seven times among devas and humans.
Ñāyena viharissāmīti manussesu upapannopi mātaraṃ jīvitā voropanādīnaṃ abhabbattā ñāyena kāraṇena samena viharissāmīti attho.
“I will live according to the right way”: even when reborn among humans, since he is incapable of killing his mother and the like, he will live rightly, justly, and properly.
Sambodhice bhavissatīti idaṃ sakadāgāmimaggaṃ sandhāya vadati, sace sakadāgāmī bhavissāmīti dīpeti.
“And there will be awakening”: this refers to the path of the once-returner, indicating that he will become a once-returner.
Aññātā viharissāmīti aññātā ājānitukāmo hutvā viharissāmi. Sveva anto bhavissatīti so eva me manussaloke anto bhavissatīti.
“I will live seeking to know fully.”
“That itself will be the end”: that will be his final life in the human world.Punadevo bhavissāmi, devalokasmiṃ uttamoti puna devalokasmiṃ uttamo sakko devānamindo bhavissāmīti vadati.
“I will become a deva again, supreme in the deva world”: he says that he will again become Sakka, king of the devas.
Antime vattamānamhīti antime bhave vattamāne. So nivāso bhavissatīti ye te āyunā ca paññāya ca akaniṭṭhā jeṭṭhakā sabbadevehi paṇītatarā devā, avasāne me so nivāso bhavissati.
“In the final existence that is going on”: in the last life.
“That will be my dwelling”: among the devas of Akaniṭṭha, the highest and most excellent among all devas in lifespan and wisdom — there will be his final dwelling.
Ayaṃ kira tato sakkattabhāvato cuto tasmiṃ attabhāve anāgāmimaggassa paṭiladdhattā uddhaṃsoto akaniṭṭhagāmī hutvā avihādīsu nibbattanto avasāne akaniṭṭhe nibbattissati.
It is said that after passing away from that state of being Sakka, having attained the path of non-returning, he will become one who goes upstream to Akaniṭṭha, being reborn in the Pure Abodes beginning with Aviha, and finally he will be reborn in Akaniṭṭha.
Esa kira avihesu kappasahassaṃ vasissati, atappesu dve kappasahassāni, sudassesu cattāri kappasahassāni, sudassīsu aṭṭha, akaniṭṭhesu soḷasāti ekatiṃsa kappasahassāni brahmaāyuṃ anubhavissati.
It is said that he will live:
- 1,000 aeons in Aviha,
- 2,000 aeons in Atappa,
- 4,000 aeons in Sudassa,
- 8,000 aeons in Sudassī,
- 16,000 aeons in Akaniṭṭha.
Thus he will experience the lifespan of a Brahmā for 31,000 aeons.