Many people seem to think that the point of Christianity is to be a better person, when in fact it is really about having a relationship with God. This does not mean, however, that being a better person is unimportant. To have a relationship with a perfect God, we must be perfect too. However, God knows that we cannot achieve this, so He sent His perfect Son as a substitute, and the Holy Spirit to make us better.
In the Old Testament, we see the old covenant (a legal term for an agreement), which God makes to Abraham and his descendants. The purpose of the covenant is seen in Exodus 6:7 “I will take you as my own people, and I will be your God”. In other words, he is promising a relationship with the nation of Israel. The history that follows shows them failing again and again to keep their side of the bargain; to keep His laws.
In the New Testament, we see the new covenant, which God makes to anyone who trusts in His Son. We see the foretelling of the new covenant in Jeremiah 31:31-34. “The time is coming,” declares the Lord, “when I will make a new covenant with the house of Israel and with the house of Judah. It will not be like the covenant I made with their forefathers when I took them by the hand to lead them out of Egypt, because they broke my covenant, though I was a husband to them,” declares the Lord. “This is the covenant that I will make with the house of Israel after that time,” declares the Lord. “I will put my law in their minds and write it on their hearts. I will be their God and they will be my people. No longer will a man teach his neighbour, or a man his brother, saying, ‘Know the Lord’, because they will all know me, from the least to the greatest,” declares the Lord. “For I will forgive their wickedness and will remember their sins no more.”
This is a much better covenant, because it does not depend on our good behaviour, but on that of the Lord Jesus. All we must do is put our faith in Jesus instead of in our selves.