It will certainly take some humility to admit that we are lacking in one thing or another.
We may say that we are not perfect but we may hesitate to say that we are not that good after all.
Even if we do say it, do we really mean what we say?
Would we be sincere enough to say that we have taken advantage of others, that we have been dishonest and told lies, that we were not responsible and lazy and pushed blame onto others.
It is not easy to be frank and to admit that we are not that good after all.
And even if we say that we are sinners, how sincere are we about it?
Jesus says in the gospel that He did not come to call the virtuous but sinners.
When we humbly admit that we have sinned and that we have criticised others for doing wrong, then we know that we are in need of forgiveness.
Then Jesus can come to heal us and save us. And we in turn can become witnesses of God's love and forgiveness for other.