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.
We are not bound by the Mosaic law anymore because Christ came and fulfilled the law. However, that does not mean we should just ignore it.
The law is fulfilled by love. "Love your neighbor as yourself." If you truly live by love, then you will strive to keep the law--not to earn salvation, but because of the salvation you have already received and to show love to others.