Is salvation is a state or process? Because I do struggle with sin pretty badly!
Salvation is a state. "Corresponding to that, baptism now saves you--not the removal of dirt from the flesh, but an appeal to God for a good conscience--through the resurrection of Jesus Christ" (I Peter 3:21).
But it is also a process. "For we are to God the fragrance of Christ among those who are being saved and among those who are perishing. To the one we are the aroma of death leading to death, and to the other the aroma of life leading to life. And who is sufficient for these things?" (II Corinthians 2:15-16). In this sense we are on our way to heaven, but we have not reach the destination yet. It is possible to get off track. "Therefore, since a promise remains of entering His rest, let us fear lest any of you seem to have come short of it" (Hebrews 4:1).
Sin always remains a problem in this world. The difference between a child of God and and child of Satan is that the child of God can't abide being sinful and works to get out of sin. The child of Satan doesn't care if he sins or not. It isn't an issue with him and he doesn't see a need to change. "If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. If we say that we have not sinned, we make Him a liar, and His word is not in us. My little children, these things I write to you, so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous" (I John 1:8-2:1).