What laws are we following

ppl always say somethig about the commandments and what the lord says to do/not do. what about hte other commandments that came along with other commandments that adulterers and fornicators should be stoned? or that apostates and false prophets shall be stoned(along with there children and women and spoil there goods; if the woman/women havent been touched keep the virgins for yourselves)....if ne1 is going to say that was the law then, what makes u think the law/a law is different now?