The Bible states that it is our faith in Jesus Christ that enables us to be overcomers:
for everyone born of God overcomes the world. This is the victory that has overcome the world, even our faith. Who is it that overcomes the world? Only he who believes that Jesus is the Son of God.1Jn.5:4-5
The Bible also teaches that faith speaks:
It is written: I believed; therefore I have spoken. With that same spirit of faith we also believe and therefore speak.2Cor.4:13
And it is the Holy Spirit who enables us to be an effective witness to Jesus:
But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth.Acts 1:8
We have a greater understanding of God and His purpose for our lives by sharing what we believe—and so we encourage every member of our Church to be active in sharing their faith:
I pray that you may be active in sharing your faith, so that you will have a full understanding of every good thing we have in Christ.Phile.1:6
Sharing our faith (either by word or deed) is called a Testimony and is simply our personal story of God has done for us.
The links from this page are a sample of testimonies from our Church.