If we are talking about one hour in a pew, a week or month, then maybe. Do we include ALL sins, whether by omission or commission? Or just the Ten Commandments? Are we talking about a normal life expectancy? If so I would have to answer by saying this. If someone told me “since I’ve accepted Jesus Christ, and repented of my sins, I have not, nor will I ever sin again.” I would have to take the escape clause, and leave any judgment of any individual’s heart to our Father, the cardio knower. Some folks have tremendous testimonies to be admired but none walk perfectly. I believe we have already seen the only perfect man and that was in our Lord Jesus Christ. A Christian may stop sinning for a time, but a life time?
I know all things are possible through God’s grace, but having said that, we all have natural tendencies that act as a head wind buffeting us as we run our own individual race.
I believe we maintain our salvation by being alert and conscious of our sinful nature and when needed repentant of our transgressions. The scriptures are full of examples of Gods willingness to forgive the sins of both the righteous and unrighteous. As Christians we have the perfect example in Jesus Christ, and while we strive to be like Him we fall short.
As for the question at hand “Is it possible for a Christian to completely quit sinning? I would say no, as I understand both scriptures and life. Just look around church…no one is there because they’re perfect, but we’re trying to get there.
Note: I have to confess this question was more challenging than I had expected it to be, it made for a great study given all the variables of any one given life. So with that said. I recommend 1st John Chapter 1 to start yours.