Can you tell the difference between believer and non-believers? Malachi

In Malachi we have the interaction between God and His people through the mouth piece of Malachi. God has a complaint with the people of God and the complaint can be summaraized and understood in the context of Malachi 3:18. God wants to do a work in the hearts of the people so that they will be "different" than other people. He wants those who believe in Him and are called by His name to be different. Through Malachi God is telling them that He is going to do this great work so that they will produce fruit of righteouness (3:3). God accomplishes this, according to Paul in Romans 5-7, through the work of Christ. The people had hardened their heart and were going through the motions of serving and loving God. God does not want motion. God wants our hearts. He sent Christ to make all this happen. He wants there to be a distinction between the person who believe in Him and loves Him and those who don't. We are not to come to God through Christ in steps, stages and half-commitments. We are to act like the God who calls us to be His. When others see your life do they see a distinction between you and those who do are not devoted to Christ? There should be a differnce.