The following quote is from Forming Intentional Disciples: The Path to Knonwing and Following Jesus by Sherry Weddell. She is quoting an Orthodox priest, Fr. Gregory Jensen:
I would argue that what typically happens is that we ask people who haven’t yet repented (and so who are not yet disciples of Christ) to take on work meant for apostles... We do this because we ourselves in the main are not disciples of Jesus Christ. Having neglected repentance in my life, I am indifferent to it in yours.
There are many components to conversion, but probably the most overwhelming, personal, and difficult to reach is the stage known as repentance. This is where a person, confronted with the truth of his or her own sinfulness and the truth of God's incredible mercy in Christ Jesus, ceases to make excuses for past actions, habits, and attitudes, and cries out for God's unconditional forgiveness.
That moment of repentance is pretty much the victory point. Anyone who does anything with evangelization knows that this is the golden moment, the payoff, for all of the work, prayers and investment. It is also the moment where the individual, moved by divine grace, intellectually and emotionally breaks with the tyrant called "the past" and embraces the promise of an eternal future full of hope.
Here's the deal, though. If you do not care about your own repentance, then you will not care about leading others to repentance. You might delight in intellectually smashing arguments against God or the divinity of Christ, but without repentance none of that matters. Literally. It does not matter.
So if you want to be an effective evangelist, then you have to be effective at repentance for your own sins. This is why we beat our breast and self-accuse during the Mass: "Through my fault, through my fault, through my most grevious fault." This is sheer confrontation with the truth of the self; no lies or excuses to rationalize my sin away. The liturgy becomes a great mirror held up so that I may clearly view myself.
But I accuse myself of sin so that grace may abound all the more in my life. These accusations of fault and sin are the proof that grace is living and active in my own heart, that God is moving in my memory and intellect and will at that moment.
Let me put it this way. If you are not repenting, you cannot be evangelizing. You need to desire the repentance of others. Remaining indifferent to it means you have perverted the apostolic work of evangelism into a self-glorifying activity. To become great at evangelization, you must first greatly desire their repentance. In order to desire repentance in others, you must first fully embrace it for yourself. This is the way of the cross, the way to freedom and restoration. There is no other way.