But that's the Old Testament
"But that's the Old Testament" is an argument used by Christians when they wish to ignore or glaze over specific Old Testament laws and stories. (This is a form of cherry-picking). It is often used when counter-apologetics bring up:
The numerous massacres performed by or under the direction of God as written in the old testament, Laws regarding the keeping and treatment of slaves, The requirement of animal sacrifices, The punishment of stoning to death, As well as any individual laws they do not wish to follow e.g.: dietary laws or the prohibition of wearing blended fabrics.
Most Christians will claim that when Jesus was died, it nullified the Old Testament laws.
This argument is flawed in two respects:
1. They continue to quote the Old Testament laws that they do wish to follow.
2. According to the New Testament (Matthew 5:19) Jesus is quoted as saying "Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least in the kingdom of heaven: but whosoever shall do and teach them, the same shall be called great in the kingdom of heaven."