(Matthew 16: 13 - 17) Now when Jesus came into the district of Caesare′a Philippi, he asked his disciples, “Who do men say that the Son of man is?” And they said, “Some say John the Baptist, others say Eli′jah, and others Jeremiah or one of the prophets.” He said to them, “But who do you say that I am?” Simon Peter replied, “You are the Christ, the Son of the living God.” And Jesus answered him, “Blessed are you, Simon Bar-Jona! For flesh and blood has not revealed this to you, but my Father who is in heaven.” Here is where Peter stated his belief in Jesus.
(Matthew 8: 28 - 29) “And when he came to the other side, to the country of the Gadarenes, two demoniacs met him, coming out of the tombs, so fierce that no one could pass that way. And behold, they cried out, “What have you to do with us, O Son of God? Have you come here to torment us before the time?” The demons that spoke out through these two unfortunates knew who Jesus is but they were no better off because of their belief because they were evil, unrepentant to the core and had been consigned to the netherworld for eternity.
(James 2: 18 - 20) “But someone will say, “You believe that God is one; you do well. Even the demons believe and shudder. Do you want to be shown, you shallow man, that faith apart from works is barren?”
So then faith, that is believing in our heart then requires some evidence, an outflowing of obedience.
The first step is repentance. When we come to a mental understanding of who Christ is and how God arranged for his suffering and death on the cross instead of us and for the sins of our lives, then the next step entails repentance as we begin to understand how repugnant the acts and motives behind some of the things we do and say are in the eyes of God. We should then have a desire to turn away from our previous ways, this then becomes an act of obedience. That is not to say that we will ever become perfect in this life, but because of our response to Christ we are imbued positionally and sealed forever with His righteousness for salvation.
Finally with that comes trust, we have shifted our trust from ourselves and our own faulty brand of righteousness to that of the righteousness of Christ himself being totally sufficient as the expiation for all of our shortcomings in this life. Not that we are in any way perfect, we are always subject to shortfalls and sins in this world. However God understands our nature and has provided for our shortcomings.
(1 John 2: 1 - 3) “My little children, I am writing this to you so that you may not sin; but if any one does sin, we have an advocate with the Father, Jesus Christ the righteous; and he is the expiation for our sins, and not for ours only but also for the sins of the whole world. And by this we may be sure that we know him, if we keep his commandments.”
These commandments aren’t something cast in stone but is that which becomes written on our hearts in knowing Jesus and as we begin to live out what we know to be right, then we are really experiencing true faith.