This is a good question and one to consider. Does Calvinism even believe in 'easy believism'? Some have attributed Calvinism to having this belief, but is it true?
The Bible talks about after people are converted, they are not to continue in sin (see Romans 6). According to the Bible, people are known by their fruits. But how do we understand the complexity of a redeemed person who still lives in a human body in a fallen world?
To make this article short and to the point, yes, some who have been converted can still sin and bring much dishonor to God (see the Corinthian church, as well as Galatians). When we are truly born again, we receive a new nature, which is intended to rule us. We have a new heart with new desires which should rule our lives and govern everything we do. At the same time, we still have an old nature and the devil who continually is before us tempting us to sin, especially in areas where we won't see our sin. That's why so many Christians, especially those in leadership positions, fall.
The Bible is very clear that we are not to continue in sin. With the power of God dwelling in us, we don't have to sin anymore. But, we do have to be vigilant and be aware of the devil's tactics, because he will always be there to tempt us with sin.
Sin is not just the obvious things we do like lying, stealing, murder, talking back to our parents, but those are all indicators of deeper roots of sin in our hearts. If we deal with our hearts, we will be dealing with pride, arrogance, hatred, anger, idolatry, selfishness, putting our desires (even good ones) before God, manipulation, dishonesty, slander, etc. When those things are in our hearts (which they, by default, usually are) we will break the 10 Commandments on a regular basis. Most of us do not even know those inner flaws are in our hearts, and if someone confronted us with them, we would be blind to them. That's why we need to be asking God to reveal our hearts to us, so we can deal with inward sin roots. But sometimes, we can still obey the commandments, even though our hearts are filled with selfishness and pride. We can only obey them outwardly and in a limited way. We can be deceived into thinking we are doing pretty good, when on the inside, we really aren't (Pharisees are a good example; the outside of the cup was clean, but inside were dead bones and crud).(
Those who attack Calvinism would claim that Calvinists believe the phrase 'Once saved. Always saved.' This is a true claim, yet, we have to understand the meaning of this phrase from the Bible. Does it mean that once a person comes to Christ, he can turn around and do whatever he or she wants? Of course it doesn't mean that. First of all, if a person has repented of their sins, and puts his or her trust in Jesus Christ as Savior, He or she will not want to go back into sin. That would be like being pulled out of a pit, only to go back into it. Why would anyone want to do that?
I have talked to people on the streets and have come in contact with those who do believe this doctrine and believe they are saved, yet they either have never repented or they think they did, but can do whatever they want now. Did these people truly come to Christ? I doubt that anyone who would go back into sin (or who wants to stay in sin) would have truly been born again in the first place. We can't skip over the repentance part of this. Furthermore, we can't trick God into thinking we have repented when we haven't. God is bigger than that and knows everything. If you are playing games with God, He will never be fooled by you. You can't ever trick Him into believing that you repented when you really didn't. God knows everything from beginning to end, well, actually He knows everything throughout eternity past, present, and future.
I think this is where the crux of the problem is. It goes back to this idol of an all-loving, all-forgiving God who people say they believe in. No wonder there will be many surprised people on That Day.
Yes, the Bible does teach that once a person is saved, he or she will not lose his/her salvation. The issue is not really one of being able to sin after you come to Christ. The issue has primarily to do with whether the person really has come to Christ and whether salvation has actually taken place in his or her own heart.
Many people trust in an action as their salvation. Many will say, after being asked if they have come to know the Lord, that they were baptized at such and such a time, or, they asked Jesus in their hearts at such and such a time. Some will even say they joined at church at such and such a time. I hope my readers know that going down an aisle, raising your hand, saying a prayer, being baptized, joining a church, or any other activity like those, as good as they might be, do not constitute salvation. Going down an aisle does not forgive your sins. But, if you are down in the front, praying for God to show mercy to you, and repenting of your sin, and turning to God, God will meet you where you are at. This whole thing has to do with your relationship to God, not something you did to mark your day of salvation.
We don't 'pray' to get saved, but we respond to God, which involves prayer. God does the saving. God can save us because we deserve to be punished eternally for our sins, but God sent His Son to take our punishment by dying on a horrible Cross (crucifixion) in our place. Just knowing this information doesn't save us. We have to respond to God by repentance and faith. And when we do this, God promises He will never leave us or forsake us, and He will completely remove all our sins. We will be washed in the blood of the Lamb of God (Jesus) and will receive robes of righteousness.
Easy believism is simply believing the Jesus died for our sins, yet, it doesn't require anything out of us. Calvinism does not believe in easy believism. The Bible doesn't teach that people can believe this way and still go to heaven after they die. Any truly born again person will see sin in a different light and it will be ugly now. The temptations to sin will still be before us and will be many, but we must learn how to say 'no' to sin, and 'yes' to righteousness. Through the process of sanctification, we grow spiritually and become more like Christ. As long as we are on earth, we will struggle against sin, yet, those who are born again will be able to resist sin and desire righteousness.
The promise of God to those who know Him, is the forgiveness of sins. He promises us that when we do sin, we have an Advocate, who is Jesus Christ, His Son. Also, if we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness (see 1 John 1). That does not mean that it is ok for us to sin. We will sin though, because of our fallen nature and the deceitfulness of sin. God will pull us out, pick us up, brush us off, and give us the power to get back on track with Him. And that is what makes grace amazing.