When you want to be a powerful witness for Christ

“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 NIV)

Witnessing becomes powerful when you give the Holy Spirit control

The passage at top says you will become a powerful witness everywhere you go when the Holy Spirit comes upon you. The key is to ask Him to fill you and to speak powerfully through you. The key is to be His ambassador and represent Him faithfully everywhere you go, expecting Him to work powerfully in and through you. 

You are a powerful ambassador as Christ makes His appeal through you 

“All this is from God, who through Christ reconciled us to himself and gave us the ministry of reconciliation; that is, in Christ God was reconciling the world to himself, not counting their trespasses against them, and entrusting to us the message of reconciliation. Therefore, we are ambassadors for Christ, God making his appeal through us. We implore you on behalf of Christ, be reconciled to God. For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God.” (2 Cor. 5:18-25ESV)

God will give you the words to speak even in the most trying circumstances 

“You will be brought before governors and kings for My sake, as a testimony to them and to the Gentiles. But when they deliver you up, do not worry about how or what you should speak. For it will be given to you in that hour what you should speak; for it is not you who speak, but the Spirit of your Father who speaks in you.” (Matt. 10:18–20)

Quote:

“If you had the cure to cancer wouldn't you share it? ... You have the cure to death ... get out there and share it.” - Kirk Cameron