HEB 10:1
The law is only a shadow of the good things that are coming - not the realities themselves. For this reason it can never, by the same sacrifices repeated endlessly year after year, make perfect those who draw near to worship.
COL 2:16 Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day. 17
These are a shadow of the things that were to come;
the reality, however,
is found in Christ.
HEB 8:5 Who serve unto the example and shadow of heavenly things,
These verses mean that the law was symbolic of Christ and everything Christ did. When Christ said he came to fulfill the law, he meant: I AM the FULLFILLMENT of all those things written in the law as symbols of ME.
For example, Sabbath is a symbol of salvation.
Hebrews 4:1 Therefore, since
the promise of entering his rest still stands, let us be careful that none of you be found to have fallen short of it.
HEB 4:9 There remains, then, a
Sabbath-rest for the people of God;
10 for anyone who enters God's rest also rests from his own work, just as God did from his.
ISA 11:10 In that day the Root of Jesse will stand as a banner for the peoples; the nations will rally to him,
and his place of rest will be glorious.
Sacrifice is a symbol of Jesus (being the sacrifice).
Don't eat bread with yeast - is a symbol of "get rid of your sins"
1CO 5:7 Get rid of the old yeast that you may be a new batch without yeast - as you really are. For Christ, our Passover lamb, has been sacrificed. 8 Therefore let us keep the Festival, not with the old yeast, the yeast of malice and wickedness, but with bread without yeast, the bread of sincerity and truth.
Circumcision is a symbol of - putting on the new person (inner person) and a cutting of an old person (flesh)
COL 2:11 * In him you were also circumcised, in the putting off of the sinful nature, not with a circumcision done by the hands of men but with the circumcision done by Christ,
GAL 6:15 Neither circumcision nor uncircumcision means anything; what counts is a new creation.
1CO 7:19 Circumcision is nothing and uncircumcision is nothing. Keeping God's commands is what counts.
I believe that pigs being unclean probably is symbolic of something like the rest of the law. I just don't know what, except maybe "unclean people", those who weren't cleansed from their sins?