Paul explains this pretty well, I think:
"And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses;
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;
And having spoiled principalities and powers, he made a shew of them openly, triumphing over them in it.
Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days: Which are a shadow of things to come; but the body is of Christ." - Colossians 2:13-17
He also talks about our liberty in Christ:
"For, brethren, ye have been called unto liberty; only use not liberty for an occasion to the flesh, but by love serve one another.
For all the law is fulfilled in one word, even in this; Thou shalt love thy neighbour as thyself." - Galatians 5:13-14
Which brings us back to the two commandments.