Sutra 3.4.40

40. But of him who has become that there is no becoming not that, according to Jaimini also, on account of (Scripture) restraining from the absence of the forms of that.

The doubt here arises whether those also who have fallen from the state of life of a Naishṭhika, Vaikhānasa or Pārivrājaka are qualified for the knowledge of Brahman or not.—They are so, since in their case, no less than in that of widowers and the like, the growth of knowledge may be assisted by charity and other practices not confined to āśramas.—This primā facie view the Sūtra sets aside. 'He who has become that,' i.e. he who has entered on the condition of a Naishṭhika or the like 'cannot become not that,' i.e. may not live in a non-āśrama condition; since scriptural texts restrain men who once have entered the Naishṭhika, etc., state 'from the absence of the forms of that,' i.e. from the discontinuance of the special duties of their āśrama. Compare texts such as 'He is to go into the forest, and is not to return from thence'; 'Having renounced the world he is not to return.' And hence persons who have lapsed from their āśrama are not qualified for meditation on Brahman. This view of his the Sūtrakāra strengthens by a reference to the opinion of Jaimini.—But cannot a Naishṭhika who, through some sin, has lapsed from his duties and position, make up for his transgression by some expiatory act and thus again become fit for meditation on Brahman?—To this point the next Sūtra refers.