Oh my, doing a bit of reading this subject began to itch at my brain. The more thoughts that came to me the more I realized a great deal can be written on this subject. A couple of thoughts that came to mind is what repentance is and what it is not. Sometimes it's helpful to consider what something is not.
Repentance is not salvation, it is either a component of or a result of salvation, or both. Repentance is not regeneration, it is not the cause of regeneration, rather regeneration leads to repentance. Repentance is not justification, it is not the foundation for justification, faith in Christ is the foundation for justification. Repentance is not many components of salvation...election, calling, glorification, etc.
However I think it falls under sanctification, and unlike other components of salvation, is not a one time event. Most importantly concerning sanctification and repentance is that although there is the command and duty, at the same time true repentance is chiefly a work brought about by God the Holy Spirit, and is so closely intertwined with faith, we may become confused about the connection to where there does not seem to be much difference between repentance and justification, but there is. Justification is the work of God alone, faith in Christ is a gift not graciously mercifully given to all. Repentance though given by God, involves the response of man, and therefore is a synergistic work, it involves God and man working in unity. Another difference is justification is a one time event, where repentance is in this life a recurring event (much could be said on this aspect alone). A couple a thoughts on why it is recurring, because we are not immutable and it is a constant reminder of our dependence on God. As Christ said; without me you can do nothing, and by this nothing truly spiritually pleasing to God the Father.
Anyway, it's getting late and just wanted to share a few thoughts, maybe get this conversation back on track.