In Acts 17 the Apostle Paul spoke to "the philosophers of the Epicureans, and of the Stoicks" who brought him to the Areopagus, otherwise known as Mars Hill, because "he preached unto them Jesus, and the resurrection." Most of them thought of the Apostle Paul as a babbler, (a little crazy). Some wanted to know more about what Paul had to say. The Apostle Paul went on to tell those men that the God they ignorantly worshipped, Paul declared to them. Then in verse 30b he told them that while God in times past had winked at their ignorance, "now commandeth all men every where to repent..." If you would be saved, repentance is not an option.
The Lord Jesus told His hearers in Luke 13:1-5, "...except ye repent, ye shall all likewise perish." Repentance is a serious issue. Without it neither you nor I can expect to make heaven our eternal home! But exactly what is repentance? Well Strong's Hebrew Greek Dictionary has a definition;