The Christian is in need of two basic things: Faith (in Christ) and Love.
The Old Covenant Laws and Commandments and Ordinances are what we have been delivered from. The only fight which the Believer is really to have is the Good Fight of Faith.
What the Good Fight of Faith basically entails is a refusal to have any part in unbelief. (when we say unbelief we mean, not believing that what Christ did at Calvary will actually, completely pay the price for our sins, give us the Righteousness of God in Christ, justify us before our Father in Heaven, and Sanctify us thoroughly).
Unbelief is the destructive force which will dilapidate the Christian. Just as rust will eat away at steel because of oxidation or rot will eat away at wood because of oxidation; one might say that the oxidation of faith is unbelief. (or belief in something other than Christ)
Many Christians I think would say the real fight is against sin.
However, Jesus has defeated sin for us already, and our death in Christ gives us His victory (Rom 7:1-4).
Under the Old Covenant the Jews fought the battle against sin but we are not to do so.
And the reason is that if we are trying to fight a battle against sin, then we are in essence saying that we do not believe that Christ took care of the sin problem at Calvary.
Indeed the reason I believe most Christians have problems in their Christian walk is actually because they are still (as the Jew did) trying to fight a battle with sin.
The problem is that the battle against sin is a battle which we can never hope to win.
The only way we can possibly win the sin battle is by fighting the Good Fight of Faith. For it is our Faith in Christ which produces His victory over sin in our lives. This victory can never, ever be produced by our own efforts (the only effort which is really meaningful is our effort in directing our faith to be exclusively in Christ), if that were possible then Christ’s death was of no value! (Gal. 2:20).
