Confident to share the gospel

Most of us most of the time are far too timid in sharing the gospel. We're afraid of many things - rejection, laughter, failure etc.
But we must counteract this fear by constantly reminding ourselves of the power of the Spirit and the gospel. That's what Paul is doing in Ephesians 3. He's reminding the Jews that the gospel is powerful enough for the Gentiles. He's reminding the Gentiles that the gospel is sufficient for them.
In verses 1 - 6, he says that though previous generations of God's people didn't know the power of the gospel, now, by the revelation given to Paul, it's clear that "the Gentiles are fellow heirs, members of the same body, and partakers of the promise in Christ Jesus through the gospel" (6).
Then he continues:

To me, though I am the very least of all the saints, this grace was given, to preach to the Gentiles the unsearchable riches of Christ, and to bring to light for everyone what is the plan of the mystery hidden for ages in God who created all things, so that through the church the manifold wisdom of God might now be made known to the rulers and authorities in the heavenly places. This was according to the eternal purpose that he has realized in Christ Jesus our Lord, in whom we have boldness and access with confidence through our faith in him. So I ask you not to lose heart over what I am suffering for you, which is your glory.

Ephesians 3:8-13

Notice that Paul didn't have a natural confidence in himself (he also says this in 1 Corinthians). But his confidence is in the the plan of God that through the church the 'manifold wisdom of God' (surely this means the gospel plan of salvation) is now being revealed 'to the rulers and authorities in the heavenly places' - i.e. to those who bind and are bound by rebellion against God.
Not only that but we can access the Lord Jesus Christ himself through faith. He is on our side!
So don't lose heart in evengelism!