John 3:30 He must increase, but I must decrease.
John brought the message of repentance while Jesus brought the message of salvation.
In order for repentance to decrease acts of sinning must decrease.
The message of salvation does not increase, it spreads to reach others.
I think this is obvious but the subtle part in this message is what changes in us as believers. Mercy and grace was poured into our lives to the point it becomes less and less about the old man or woman we were and about how much better our lives are with Christ in it.
People do not need to know how bad I was in order to see how much better my life is now in Christ. All I have to do is let Him do what I cannot do myself.
Love the lost.