US-P18.016ab ।US-P18.016cd ॥
In plain words
The inference is that this person, free of suffering, has already cultivated contemplation in earlier lives. Otherwise our conduct would have no scriptural ground — and if that were how things stood, the result is one we cannot accept.
Close to the Sanskrit
That sorrow-free person is inferred to have practised contemplation in previous bodies. Our conduct would otherwise be ungrounded in scripture; such a consequence is undesirable.