1. Should we still observe the Law?
Once we understand the Law, we can answer that question for ourselves. 1 John 3:4 said “Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.” Since sin still exist, so should to the Law.
Apostle Paul also stated
“What shall we say then? Is the law sin? God forbid. Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet.”-Romans 7:7
You know what is pleasing or unpleasing to the Father by looking at the Law.
2. I thought that Law was nailed to cross.
There was a Law that was nailed to the cross, however, it was not the written Law of Moses which is also known as the Law of God (Nehemiah 8:8, 18), since it was God who gave it. 
Colossians 2:14 said “Blotting out the handwriting of ordinances that was AGAINST US, which was contrary to us, and took it out of the way, nailing it to his cross;” His Law was never against us. It was given as a blueprint to show us how to love him. Christ even said, :If ye live me KEEP my commandments (John 14:15)
3. I was taught that there were only two commandments that I have to keep; To love the Lord God with all my heart and to love my neighbor (Matthew 22:36-40.
People he refuse to keep the Law often read some verses of the Bible while omitting other verses. The question asked to Christ by the Pharisees was “Which is the great commandment on the law? Christ response was not “Why are you asking me this, since I came, we no longer have to keep the Law. He began his answer by saying “This is the first and great commandment….The commandments of God are broken up into sections and this is a summary of the entire Bible; how you should treat God and how you should treat your fellow man. Christ concluded by saying “On these two commandments hang all the law and the prophets.
4. How can you be so sure that the Law was not against us?
Christ himself said THINK NOT I come to destroy the LAW or the prophets: I am not come to destroy, but to fulfil. Fulfill here means to DO. It does not mean to end. How do we know? Because he just said don’t think that I come to destroy it. He goes on to state “Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled (Matthew 5:17-18). Since the heavens and earth still exist, so too does the Law.
5. Did any of the other Apostles speak in favor of the Law?
Apostle Paul said in Romans 7:12
“Wherefore the law is holy, and the commandment holy, and just, and good.” Anything that is holy and good was never against us!
6. Why did the Bible say “For Christ is the end of the law for righteousness to every one that believeth? Didn’t his coming free us from the Law?
This is one of the biggest reasons people reject the Law of Moses. What they are unaware of is that the word LAW is used several different ways. He is the end of 
the Law, so the question one should ask is WHAT LAW? Look at what Romans 8:2 said:
“For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death.”
7. There are a few Bible verses that said we are no longer under the Law. How do you explain?
To really understand this phrase “under the law”, we should visit Galatians 3:10.
“For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not IN ALL THINGS WHICH ARE WRITTEN IN THE BOOK OF THE LAW.
It is the works of the Law ONLY that puts you under the curse. Works without faith is dead, so is faith without works (James 2:18-20,24-26). James explains that faith alone does not justify you, and works alone does not justify you. Therefore, understanding James better helps us understand Galatians and vise versa. Let’s not ignore then, that Galatians said that everyone that continueth not in all things which are written in the book of the Law is cursed.
8. What about animal sacrifice? That was part of the Law, so are you saying that we still have to observe that?
Animal sacrifice fell under the category of Old Covenant. The Old covenant was a temporary covenant, that when it was given, it was designed to phase out during the ministry of Christ (Hebrews 8:13). Unfortunately, when people mention the Law, the first thing that they think about is animal sacrifice.