The basic explanation is as follows.
The samyojana of “Silabbata Paramasa” is of two types.
- “sīlassa sīlabbataparāmāsa” is the lower type. Someone with this type seeks rebirth in Deva or Brahma realms by following mundane moral guidance (five or higher precepts) or cultivating anariya jhanas. For example, they may even abstain from sensual pleasures to cultivate jhana.
- “suddhassa sīlabbataparāmāsa” is the higher type (less bondage to the rebirth process). Here, one is abstaining from immoral conduct because they realize those can only result in bad outcomes; they may abstain from enjoying sensual pleasures because they can see that those can lead to immoral conduct. Thus they avoid immoral deeds or abstain from sensual pleasures, not for the sake of seeking rebirths in Deva/Brahma realms. They are purified (suddha) to a greater extent. However, (probably since they may not have heard the correct version of Buddha Dhamma), they do not comprehend the 4NT/Paticca Samuppada/Tilakkhana and thus cannot proceed to Nibbana.
Sadhu
The Maha Govinda Sutta, Dn 19, might be a pleasing illustration to it, like many other occasion where the Sublime Buddha taught Devas and Brahmas. (the is ‘sadly’ no real given translation into english toward the Buddhaparisa headed by the Sangha, as far as aware.)
(Samana Johann)