{Ashes} (spodos). Old word, in N. T. only here,  Mt 11:21  Lu 10:13 . Common in LXX. {Of a heifer} (damale(9373)). Old word
(damalis), a red heifer whose ashes mingled with water (meta
hudatos, verse  19 ) were sprinkled (
antizousa, present
active participle of 
antiz(935c), in LXX, though 
ain(935c) more
common) on the contaminated or defiled ones ( Nu 19 ) as the
blood of bulls and goats was offered for sins ( Le 16 ).
{Sanctify} (hagiazei). First-class condition, assumed as true.
This ceremonial ritual does serve "for the cleansing
(katharot(8874)a, old word here only in N.T.) of the flesh," but
not for the conscience (verse  9 ). The cow was am(936d)on, the
individual katharos.