Luke 9:23

And He was saying to them all, “If anyone wishes to follow Me (as My disciple), he must deny himself (set aside selfish interests) and take up his cross daily (expressing willingness to endure whatever may come) and follow Me.  

As Christians, our call is to be disciples of Jesus. Discipleship means denying our old selfish ways and sins and not letting them return. Being born again will change our hearts, but our minds must be renewed. This is why we must take up the cross daily and endure whatever comes as we follow Jesus.