Quora: "Where in the Bible does it say that the Levitical laws of the Old Testament were canceled?"

It specifically says they are not:

“Is any man called being circumcised? let him not become uncircumcised. Is any called in uncircumcision? let him not be circumcised.” - 1 Corinthians 7:18

Thus the Jews who believe in Christ are commanded to continue in all the customs that Moses gave them, and those who are not circumcised should not enter into that covenant.

Something to realise is that many of the mosaic customs require the Temple, and are forbidden without it. For example, the circumcised are forbidden to make altars and offer sacrifices except in certain places. An uncircumcised believer like myself could build an altar in the backyard and sacrifice a bullock in worship if I so chose, like Naaman.