Sri Aurobindo
Letters of Sri Aurobindo
09. Transformation of the Physical (2)
Fragment ID: 3487
That is correct – if the sex-fluid is prevented from being spent away, it turns into tejas and ojas. The whole theory of brahmacarya is based upon that by the yogis. If it were not so, there 



would be no need of brahmacarya for producing tejas and ojas.
It is not a question of vigour and energy per se, but of the physical support – in the physical support the ojas produced by brahmacarya counts greatly. The transformation of the retas into ojas is a transformation of physical substance into a physical (necessarily producing also a vital-physical) energy. The spiritual energy itself can only drive the body, like the vital and mental, but in driving it it would exhaust it if it has not a physical support. (I speak of course of the ordinary spiritual energy, not of the supramental to be, which has not only to transmute retas into ojas but ojas into something more sublimated.)