Two things

ye see that two things are required to begin a Christian man. The first is a steadfast faith and trust in Almighty God, to obtain all the mercy that he hath promised us, through the deserving merits of Christ's blood only, without all respect to our own works. And the other is that we forsake evil and turn to God, to keep his laws and to fight against ourselves and our corrupt nature perpetually, that we may do the will of God every day better and better. 

(Tyndale's Preface to the New Testament, p20-21)