We all are great sinners, not only because all have sinned and fall short of the glory of God, indicating that great divide between God and man, but also because despite having begun the walk of faith still do stumble and fall.
We ought to live our lives with a reputation, not of proclaiming sainthood, only inwardly with God if true, but proclaiming rather our sins.
I am the greatest sinner in some regards, yet pursuing holiness nonetheless. For as the Beloved Apostle writes, If we say we have no sin, we deceive ourselves, and the truth is not in us.