Pahlavi Texts, Part II (SBE18), E.W. West, tr. , at sacred-texts.com
1. The eleventh question is that you ask thus: Does the growth of a good work eradicate sin just like the original good work, or not?
2. The reply is this, that the growth does eradicate it, as happens with the good work which is for atonement for sin; it shall be done as retribution for sin, and it eradicates the sin, which is specially mentioned in revelation 5. 3. 'Then the place of his
other good work is evidently the soul; and, in order to be with the sin at its origin, it remains and is taken into account.' 4. 'Through good works and the growth of good works is the recompense of the soul, so that they should do those good works in atonement for sin.' 5. And concerning the sin eradicated it is said: 'An original good work eradicates original sin 1, and the growth of a good work eradicates the growth of a sin.'
30:5 See Pahl. Vend. VII, 136, where the matter is mentioned, but p. 31 the passages which seem to be quoted here must be from some other source.
31:1 Literally 'sinning of the beginning' (bûn-vinâsîh). It must mean the first commission of any particular sin, and has no connection with the 'original sin' of Christian writers.