We are, each of us, in the same position that Mormon describes in this chapter. We are all in open rebellion against God (despite our potential desires not to be). Our only hope of Salvation is to repent and humble ourselves before Him – we must do it today, and if we do it today, we must do it again tomorrow. We must do it over and over and over again throughout the eternities until such time as the Father welcomes us back home.
We can never repent enough today to remove the necessity of repenting tomorrow. And no obedience of yesterday removes the necessity that we repent today.