Romans 3:1
Then what is the Jew's superiority? What is the good of circumcision?
Romans 2:25-29
Circumcision is certainly of use, provided you keep the Law; but if you are a breaker of the Law, then your circumcision is turned into uncircumcision.
1 Corinthians 15:32
What would it avail me that, humanly speaking, I 'fought with wild beasts' at Ephesus? If dead men do not rise, let us eat and drink, for we will be dead to-morrow!
Hebrews 13:9
Never let yourselves be carried away with a variety of novel doctrines; for the right thing is to have one's heart strengthened by grace, not by the eating of food ??that has never been any use to those who have had recourse to it.