There are over 600 commandments or Mitsvot that God gave to the Jewish people. It is very difficult (if not impossible) to keep all these commandments.
But the reason God gave these commandments was to show that God’s standards are very high and perfect. These commandments serve as a tutor for the Jewish people of how they should live. We know there are two ways for a person to live before God forever.
By keeping all the law, or
By faith and repentance
Because you believe in Jesus, you already know that trying to live by keeping all the law is not possible. Humans are weak and frequently fail. And the blood of animals can never atone for the sins of the soul (Hebrews 10:4).
“For as many as are of the works of the Law are under a curse; for it is written, ‘Cursed is everyone who does not abide by all things written in the book of the law, to perform them.’ Now that no one is justified by the Law before God is evident; for, ‘The righteous man shall live by faith.’ However, the Law is not of faith; on the contrary, ‘He who practices them shall live by them.’” (Galatians 3:10-12)
So from these words, we know that no one is able to be justified by the law. But he who practices faith shall live.
The concept of the righteous shall live by faith is not new. In fact, it was given to Abraham.
“Then he [Abraham] believed in the Lord; and He reckoned it to him as righteousness.” (Genesis 15:6)
Abraham believed that God would bless all the world through his seed. He believed in the blessings of the Messiah to come. In fact, “The Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, ‘All the nations will be blessed in you.’” (Galatians 3:8)
So even Abraham heard a brief version of the gospel that through his seed all nations would be blessed. And Abraham believed God’s words. Therefore, he is the father of faith to all who believe.
Furthermore, the prophet Habakkuk said many years before Christ:
“Behold, as for the proud one,
His soul is not right within him;
But the righteous will live by his faith.” (Habakkuk 2:4)
So a form of the gospel has been preached since ancient times. Then the gospel was fully preached when Christ came.
Therefore, since we have the good news with us, not even a Jewish Christian needs to keep the ceremonial laws.
Peter (a Jewish man) lived like a Gentile (Galatians 2:14). And the apostle Paul (a Jew from the tribe of Benjamin) chose to live in the same way as the people who would accept Christ: “To the Jews I became as a Jew, so that I might win Jews; to those who are under the Law, as under the Law though not being myself under the Law, so that I might win those who are under the Law; to those who are without law, as without law, though not being without the law of God but under the law of Christ, so that I might win those who are without law. To the weak I became weak, that I might win the weak; I have become all things to all men, so that I may by all means save some.” (1 Corinthians 9:20-22)
Paul kept the law sometimes in order to win Jews and he did not keep the law sometimes in order to win Gentiles. Paul did not see the Mitsvot as something binding upon himself, but he bound himself to the law of Christ.
What is the law of Christ then?
There are many commandments from God in the Bible that does not have to do with washings, food, keeping clean, celebration of special days, or circumcision.
These commandments such as:
“Do not make for yourself an idol or worship them” (Deuteronomy 5:8),
“Honor your father and mother” (Deuteronomy 5:16),
“Do not commit murder” (Deuteronomy 5:17),
“Do not commit adultery” (Deuteronomy 5:18),
“Do not steal” (Deuteronomy 5:19),
“Do not covet” (Deuteronomy 5:21),
“Treat others the same way you want them to treat you.” (Luke 6:31)
“Trust in the LORD with all your heart” (Proverbs 3:5)
all apply to us today. These commands and others in the Bible, which focus on our hearts to love God and love others, fall under the law of Christ. Furthermore, we are to grow in the fruit of the Spirit, which is “love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law” (Galatians 5:22-23).
We live by faith and repentance. By faith in Christ who died for our sins on our behalf, and made atonement for us before God the Father. By repentance, which is to turn away from sins and follow Jesus from now on, living a life worthy of His calling.
If we have any sins, we can ask God for forgiveness and work with Him diligently to overcome those sins (1 John 1:9).
The Bible warns against being legalistic regarding the Mitsvot.
"But now that you have come to know God, or rather to be known by God, how is it that you turn back again to the weak and worthless elemental things, to which you desire to be enslaved all over again? You observe days and months and seasons and years. I fear for you, that perhaps I have labored over you in vain." (Galatians 4:10)
"Therefore no one is to act as your judge in regard to food or drink or in respect to a festival or a new moon or a Sabbath day— things which are a mere shadow of what is to come; but the substance belongs to Christ." (Colossians 2:16-17)
So what is important is to love God and love others (Matthew 22:37-40). That is the heart of all the commandments, and it is not about food or drink, celebration of days, washings, or clean/unclean regulations.
Out of all the Mitsvot, the apostles gave the Gentiles the following command:
“For it seemed good to the Holy Spirit and to us to lay upon you no greater burden than these essentials:
that you abstain from things sacrificed to idols and from blood and from things strangled and from fornication; if you keep yourselves free from such things, you will do well. Farewell." (Acts 15:28-29)
You can choose to do what Gentile Christians do, who follow the law of Christ with just these essentials from the Mitsvot.
Or you can follow the law of Christ, and keep by choice some of the Mitsvot and celebrate some of the feasts of God and traditions from ancient times. But in keeping some of these traditions, it is not to be saved by law, but to celebrate and remember the Lord.
There are indeed many deep and beautiful meanings in the traditions and feasts God gave to Israel.
God has given days and festivals to the Jewish people, because God wants us to remember His goodness to the Jewish people whom He set free from slavery in Egypt, and His goodness to all who believe whom He set free from sin through God the Son. So in the future, Jews and Gentiles will most likely be celebrating these festivals in God's kingdom in remembrance of what God did.
You can see some of the symbolism and meanings of Jewish feasts that point to Christ here:
https://www.gotquestions.org/Jewish-feasts.html
“The one who eats is not to regard with contempt the one who does not eat, and the one who does not eat is not to judge the one who eats, for God has accepted him. Who are you to judge the servant of another? To his own master he stands or falls; and he will stand, for the Lord is able to make him stand.
One person regards one day above another, another regards every day alike. Each person must be fully convinced in his own mind. He who observes the day, observes it for the Lord, and he who eats, does so for the Lord, for he gives thanks to God; and he who eats not, for the Lord he does not eat, and gives thanks to God. For not one of us lives for himself, and not one dies for himself; for if we live, we live for the Lord, or if we die, we die for the Lord; therefore whether we live or die, we are the Lord’s. For to this end Christ died and lived again, that He might be Lord both of the dead and of the living.” (Romans 14:3-9)