Thank you for bringing this issue for discussion, Saket. Thank you for the comment, Tobi.
1. Waharaka Thero has discussed this issue of “kamma vipaka can materialize up to 91 maha kappas.” However, as I recall, that does not apply to janaka kamma, i.e., those that can lead to rebirth.
- There is a sutta that discusses the issue of “kamma vipaka can materialize up to 91 maha kappas.” As I recall, it involves King Bimbisara. He saw a dream where a group of petas came to him and asked for his help to be released from the peta realm. The Buddha explained to the King that he can indeed help them because they had helped him within the past 91 maha kappas.
- The point is that this 91 maha kappa limit does not apply to janaka kamma (those leading to rebirth.) The reference in that sutta is to kamma vipaka appearing during a lifetime.
2. In general, an aparāpariyāyavedanīya kamma (that can bring rebirth) may be indefinitely effective, as Tobi pointed out. Of course, it may wear out after millions of maha kappas, but no such limit is specifically stated.
3. Tobi wrote: “So no Hadaya Vatthu in Arupa Loka.”
- That is not correct. Citta cannot arise without a rupa. An arupi Brahma has the smallest rupa, hadaya vatthu.
- Viññāṇa (i.e., citta) cannot arise without being accompanied by rupa, vedana, saññā, and saṅkhārāra: “Upaya Sutta (SN 22.53)” and subsequent few suttas.
- That quoted verse can be improved as “Without accompanied by rupa, vedana, saññā, and saṅkhārāra, the establishment, growth, or the movement of viññāṇa is not possible.”
4. I have revised the two posts Saket quoted. Thanks again to Saket for pointing that out.