James, the brother of Jesus, said that we are saved by God’s grace (God’s unmerited favor) and actions that confirm the change Jesus has made in us. It is true that there is no limit to God’s grace. The first thing I thought of when I learned this was, “I can sin all I want and still go to heaven.” While that is true you must examine yourself to see if Jesus really does live in you and is one with you.
If you are truly saved, if you have received a new spirit from Jesus and are one with Him then you have been fundamentally changed and will not want to sin. You will want to do God’s will. If you do sin it is not really you doing it but sin doing it. You will be heartbroken that you have hurt your Savior. You will confess your sin to Him and thank Him that He forgave you on the cross two thousand years ago. He will restore you. You will thank Him for being your Friend that sticks closer than a brother. You will not want to sin again.
However, if you are not truly saved and you think you are, and you think that you can sin all you want because grace covers it all, then you won’t care that you have hurt God and others, you think it’s all covered by grace anyway and you will sink deeper and deeper into sin and gradually lose the ability to hear God’s voice of conviction.
If you act like God’s grace can be used to sin without consequence, you are most likely NOT a Christian now and never were.