“Therefore, brothers, we have an obligation —but it is not to the sinful nature, to live according to it. For if you live according to the sinful nature, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live,” (Rom 8:12, 13)
It couldn’t be clearer.
“This is the message we have heard from him and declare to you: God is light; in him there is no darkness at all. 6 If we claim to have fellowship with him and yet walk in the darkness, we lie and do not live out the truth.” (1 John 1:5, 6)
“No one who lives in him keeps on sinning. No one who continues to sin has either seen him or known him.7 Dear children, do not let anyone lead you astray. The one who does what is right is righteous, just as he is righteous. 8 The one who does what is sinful is of the devil, because the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the devil’s work.” (1 John 3:6-8)
“Don’t you know that when you offer yourselves to someone as obedient slaves, you are slaves of the one you obey—whether you are slaves to sin, which leads to death, or to obedience, which leads to righteousness? 17 But thanks be to God that, though you used to be slaves to sin, you have come to obey from your heart the pattern of teaching that has now claimed your allegiance.” (Rom 6:16, 17)
“...thanks be to God that, though you used to be slaves to sin, you have come to obey from your heart the pattern of teaching that has now claimed your allegiance.”
Paul begins the book of Romans by saying he has been made an apostle to
“call people from among all the Gentiles to the obedience that comes from faith.” (Rom 1:5b)
Notice he doesn’t call them to faith. He calls them to obedience. But it’s an obedience “that comes from faith.” (Paul also finishes the book of Romans by making mention of “the obedience that comes from faith.” See Rom 16:25-26.)
“By faith Abraham, when called to go to a place he would later receive as his inheritance, obeyed and went...” (Heb 11:8a)
There is no such thing as faith without obedience.
“What good is it, my brothers and sisters, if someone claims to have faith but has no deeds? Can such faith save them?” (James 2:14)
James goes on to show that such a faith saves no one.
It is true that faith is a gift (Eph 2:8-10), but it is a gift which is shown to be received, only when it is accompanied by obedience. When we do what Jesus says, we are showing that we have faith in him. Faith expressed as obedience, is the only kind of faith that saves a person from sin.
Faith is a gift from God; and so is the obedience that comes from faith. I can’t do what God commands; but Christ can—and he is in me. (That's why no one has reason to boast. It is God who works in us to will and to act according to his good purpose (see Phil 2:13, see also Phil 4:13 and John 15:5). We are unable to obey God (see Rom 7); but when we accept that Christ can do all things and we let him work through us we become new men. We begin to overcome (see Rev 21:7, 8), and are “transformed into his image with ever-increasing glory” (see 2 Cor 3:18).
"Yes, but we still sin.”
We do, but if we do not continue to confess our sins and repent of them, we will not overcome, and we will die in our sins (see 1 John 1:7-9). He purifies us from sin through repentance. (And slowly makes us like Christ.)
“But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus, his Son, purifies us from all sin.” (1 John 1:7)
According to 1 John 1:7, Jesus purifies us from sin "if we walk in the light." Our purification from sin is conditional upon walking in the light. (Notice how fellowship (i.e. right relationships), plays a part. To be right with God we must love and forgive each other. See Matt 5:23; 6:15) If we are not walking in the light we are dead in our sins. (If we are not walking in the light, accepting a theory of atonement will not save us. See here.)
In all the epistles, the apostles are talking to two groups of people, those who are walking in the light, and those who are not. Over and over again they say those who walk in the light will inherit eternal life; and those who continue to sin will die. (The verses quoted above are but a small sample.)*
Does this mean we can be justified by keeping the law? Not at all.
All who rely on observing the law are under a curse, for it is written: “Cursed is everyone who does not continue to do everything written in the Book of the Law.”(Gal 3:10)
Paul is talking about winning God’s approval through keeping the law of Moses. (If you break just one law you must be punished.) He is not saying we don’t have to obey Jesus to be saved from sin. (Paul was under Christ's law. see 1 Cor 9:21.) Scripture is very clear, we must have a loving obedient relationship with Jesus to be saved from sin. Does this mean we have to be perfect to be accepted by him? Not at all. He is pleased when we try to do what he asks; he regards our trying, and our confessing our sins and repenting of them as obedience (see here).
There is no such thing as being saved from sin without obedience. To say you are saved from sin while living in sin, is like saying you have been saved from alcohol while getting drunk every night. Jesus came to save us from sin; he did not come to save us from the consequences of sin. The natural consequence of sin (sooner or later) is misery. Jesus did not come to save us from the misery which sin causes while we continue to live in sin. And neither did he come to save us from wrath, punishment, and death. If a person continues to live in sin, wrath, punishment and death do await them. (But those things too are motivated by God's perfect love, and will ultimately play a part in saving that person from their sin. The wise don’t ask themselves whether or not they have faith, they simply acknowledge that without Jesus they can do nothing and then begin to let him work through them by trusting that he will take care of them and doing what he tells them to do. The person who try’s to do what he asks and fails will seek God’s help (if they are serious about following Jesus, see examine yourself and prayer).)
Satan is very clever; he has managed to undermine Jesus direct commands by getting Christians to think that they don’t have to obey to be saved from their sins. There is no salvation from sin without a loving obedient relationship with Jesus.
The false gospel says you can be saved from the consequences of sin, without turning from your sin (without trusting and obeying Jesus). If we are not obeying Jesus we should not assume that we have entered into life.
“But if this is true, How can anyone be sure of their final destination?”
I am sure of my final destination. And I'm sure I am forgiven. See here.
* There are two senses in which people are in Christ; one sense applies to all people and one applies only to those who trust Jesus. Obviously (above) I’ve been referring to those whose behaviour reflects their trust in Jesus. Everyone on this earth is loved by God and forgiven. (There are also two senses in which God forgives. See here.) Once a person knows they are loved and forgiven they want to trust Jesus. Knowing what God is like makes us want to be in his Kingdom. (We are all welcome in his Kingdom but none of us want to be with God until we know that God is truly good.) For an in-depth look at the sense in which all people are in Christ read Jesus Unforsaken by Keith Giles.