The definition goes like this: Grace is the unmerited love and mercy of God toward sinners. In Romans Paul said it like this: " ...God demonstrates His own love toward us, in that while we were still sinners, Christ died for us." NKJV, Romans 5:8. Before he knew there would be any believers, he paid the cost of sin before God. That's grace. God pours out salvation on sinners when they just ask. There are no trial memberships. We are accepted on our word alone.
Now is there a catch? Sort of. God does not require any payment or level of performance, but he does indicate that we must ask for what he has to offer. 1John 1:9 says that he will forgive our sins when we confess. That's all. We confess that we are sinners and he forgives the sin. We live in a litigious society--there must be more to it that that. Well, there is. He will not allow us to stay in the state of sin he found us in. He wants us to become a reflection of himself He wants us to be pure. "Be perfect as your father in heaven is perfect." That doesn't sound like he is satisfied with just any old confession. Watchman Nee uses the illustration of a draftee versus a volunteer. Once we are Christians we are obligated to become like him. We have to wear the uniform and conform to the rules. He accepts us in whatever condition he finds us, but his will is to change us to what he wants us to be.
Now let me return to grace. By grace we are saved, and by grace we are united with him. Then by grace we are changed to become what he wants us to be, and the change may be, probably will be, a painful and daunting metamorphosis. He will love us, but never doubt that you will be different than he found you when this is all over, and that what you will become is not what you envisioned when you began.