Luke 2:15-20 (ESV)
When the angels went away from them into heaven, the shepherds said to one another, "Let us go over to Bethlehem and see this thing that has happened, which the Lord has made known to us."  And they went with haste and found Mary and Joseph, and the baby lying in a manger.  And when they saw it, they made known the saying that had been told them concerning this child.  And all who heard it wondered at what the shepherds told them.  But Mary treasured up all these things, pondering them in her heart.  And the shepherds returned, glorifying and praising God for all they had heard and seen, as it had been told them.
“And when they saw it they made known the saying that had been told them concerning this child.”
Evangelism, this is what I think when I read this. Telling others the good news. Telling others what you believe. I think it is only natural. In fact one reason I think that the church suffers growth is that we have tried to turn evangelism into a program. We think people need to be trained for it and so on. It doesn’t need to be so hard. It is as simples as telling others what you have been taught in church. That is it. Don’t force the conversation, just let it happen. It will. Invite them to church. Tell them what you hear. It’s good news. Good news wants to be shared. People like sharing good news. And this is good news that never wears off because it is constantly being applied anew. This little child laid in a manger, whom the Lord made known to shepherds in the field, he has been made known to us. In knowing him our sins have been forgiven by this little child, because he died for our sins, and rose victorious over death that we might live.