These things happened to them as examples and were written down as warnings for us, on whom the culmination of the ages has come.  So, if you think you are standing firm, be careful that you don’t fall!
(1 Corinthians 10:11-12)

In this day and age, we can't say that we "didn't know."  We have the Bible, God's sacred word, and all of the lessons containing the consequences of actions, both good and bad.  We know that God forgives us if our hearts are truly repentant, but that isn't a free card to do as we please, then ask for forgiveness.  He wants us to learn from our mistakes, change our direction, and set a good example of Christlike behavior.