I have been thinking about this very thing. I believe we can be a witness by the way we live and the way we act. Matthew 7:20
Wherefore by their fruits ye shall know them.
Galatians 5:22
But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith,
Ephesians 5:9
(For the fruit of the Spirit is in all goodness and righteousness and truth;
2 Corinthians 5:20
Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ's stead, be ye reconciled to God.
Actions speak louder then words. People are hungry for the spirit that is why we have to be the fruit that attracts them.