"There is a dangerous and entirely baseless sentiment abroad which assumes that every teaching of Christ must be binding during this age simply because Christ said it. The fact is forgotten that Christ, while living under, keeping, and applying the law of Moses, also taught the principles of His yet future kingdom, and, at the end of His ministry and in relation to His cross, He also anticipated the teachings of grace. If this three-fold division of the teachings of Christ is not recognized, there can be nothing but confusion of mind and consequent contradiction of truth."
– Lewis Sperry Chafer, Grace

There are three separate systems that Jesus taught while he was here on earth: The law from Moses, the law of the Messiah's kingdom, and the teachings of Grace.  It is very important that these three systems not be mixed and this is why:

A misunderstanding about the system God is expecting us to live by today can stop a Christian's effectiveness in the world.  We can expect that Satan would use these misunderstandings to frustrate the work of Jesus on the earth today.  Not only this, but attempting to live by an inappropriate system can lead to a frustrating life as a Christian instead of the promised abundant and victorious life (even in physical suffering.)   So, which system are we in now?

It is important to know that the system that we now live under was described in the upper room by Jesus to his disciples (John 14), and later, was explained in the doctrine of the New Testament by the disciples.  Paul was the one who was given the greatest work in this area of Bible-writing.  The system that we live under can be called:  "Grace."  The age we live in is often called the "Age of Grace."  But why would following one of the other systems have such a bad affect on Grace?

Both the law from Moses and the law of the Messiah's Kingdom are legal systems.  Grace, on the other hand, is not.  In fact, attempting to follow a legal system with Grace, corrupts the both systems (Galatians 2: 18-21).  One of the key elements of legal systems is that they condition the government’s favor on your performance (Leviticus 26).  You have to fulfill "your end of the deal."  Christianity, however, does not work like this.  Your blessing is based on Christ’s performance (Romans 8: 3, 4) .  The closest thing to "your end of the deal" is that you must believe and accept his work for you (John 6: 29).  If you attempt to do anything to secure your position with God you fall away from Grace (Galatians 5:4).

Christians can be confused by false teaching.  Some of these false teachers may not even realize that that is what they are, but even if they don’t, we are told as believers to watch out for them.  False teachers teach wrong things about Jesus; why He came and what He did.  These teachers seem like very good people and are nice on the outside.

Live by Grace and live in victory.  For more information on this read “Grace” by Lewis Sperry Chafer.