“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)
“By faith Abraham, when called to go to a place he would later receive as his inheritance, obeyed and went...” (Heb 11:8a)
“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)
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.
We do, and if we are not confessing our sins and repenting of them, 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)
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.)
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)
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 salvation from sin without a loving obedient relationship with Jesus.
“But if this is true, How can anyone be sure of their final destination?”