I have been a vegetarian for several years, and I have been wondering with Easter approaching, if it is a sin not to eat lamb for the Easter celebration?
Since the Bible never specifies that there be any celebration on Easter (nor even designates a holiday of Easter), there could not be any sin in eating or not eating anything on that day. It would be like saying it was a sin not to watch fireworks on the Fourth of July (which, of course, only the United States celebrates) or Chinese New Year, neither of which the Bible mentions.
At the price of lamb these days, the last time I at lamb was at a Passover celebration a couple of years ago. Since I am not Jewish, I am not required to eat it even then.
While God did restrict what the Jewish people were to eat, for all non-Jews there are no food restrictions, even for Christians. "For one believeth that he may eat all things; another, who is weak, eateth herbs. Let not him that eateth [meat] despise him that eateth not; and let not him which eateth not judge him that eateth; for God hath received him." (Romans 14:2-3) Paul tells those of us who are carnivores not to look down on vegetarians, nor vegetarians to condemn meat eaters. In verse 17 of the same chapter he says, "For the kingdom is not meat and drink; but righteousness, and peace, and joy in the Holy Spirit." Read the whole chapter for Paul's full discussion on the issue.