{Until seventy times seven} (he(9373) hebdom(886b)ontakis hepta).
It is not clear whether this idiom means seventy-seven or as the
Revised Version has it (490 times). If heptakis were written it
would clearly be 490 times. The same ambiguity is seen in  Ge
4:24 , the LXX text by omitting kai. In the _Test. of the
Twelve Patriarchs, Benj._ vii. 4, it is used in the sense of
seventy times seven. But it really makes little difference
because Jesus clearly means unlimited forgiveness in either case.
"The unlimited revenge of primitive man has given place to the
unlimited forgiveness of Christians" (McNeile).