God gave us the law to help us know what is right and what is wrong for our good. When we live according to the law we are blessed and when we rebel we live under curse. However God also knew that because of sin we would be unable to fulfil the law. Therefore He sent His Son Jesus as a sacrifice to cancel the power of sin over us. We are now living under grace and the law does not have the power of sin to cause us to sin. This is the shift that occurred at Calvary. Now we can choose to continue to live under the law or under grace.
Law
The law is a slave driver. It demands us to keep it at any cost. When we fail it makes us guilty and no amount of confession seems to work to satisfy our conscience. Sin working through the law drives us to extreme ends and some have been pushed to suicide to satisfy its demands. Many still live under the law despite having experienced the new birth by grace through faith. Our spirit was saved but our soul continues to be saved. This disconnect between our spirit and our soul is what causes a lot of confusion in us. Once we realise this we will become more determined to walk in the spirit and not in the flesh. The flesh prefers to walk under the law than under grace.
Grace
Grace is a completely different mindset. Grace receives freely all that God has already prepared for us. We rest in His finished work on the Cross. He did it all for us and we can rest in His completed work. There is no more pressure to do like under the law. Grace enables us to fulfil the law without an internal struggle. What a difference in our walk when we surrender all to the Spirit and allow Him to lead us and guide us. Let us pursue to live our lives under grace and not get back to serving our old master.