as knowing this, that law is not made for a righteous man, but for the lawless and insubordinate, for the ungodly and sinners, for the unholy and profane, for murderers of fathers and murderers of mothers, for manslayers,
For manslayers ...  This is a clear reference to the sixth commandment; but here again there is a significant difference in the law of Moses and the law of Christ.  Whereas the law of Moses forbids "murder," it is the lesser charge of manslaughter that surfaces here.