Some have argued that if salvation is absolutely free, without any effort on our part, then it would lead to abuse. In other words, a person could claim to believe in Jesus while holding on to his old sinful habits. Therefore it is inconceivable that God intended salvation to be this way in view of its adverse consequences.
While it is true that since salvation is free it could lead to abuse, this is by no means a reason why it cannot therefore be free. Paul himself realizes the potential of grace being abused.
Gal 5:13 You, my brothers, were called to be free. But do not use your freedom to indulge the sinful nature…(NIV)
1 Pet 2:16 Live as free men, but do not use your freedom as a cover-up for evil…(NIV)
Paul’s understanding of the abuse of grace does not stop him from preaching salvation through grace. It only resulted in him urging the believers not to take advantage of the position. In conclusion, it can be said that the fact that grace can be abused actually proves that salvation is free. If salvation involves our obedience to Christ by doing good, how can it possibly be abused?