Acts 1:8
And you shall receive power after the Holy Ghost is come upon you, and you shall be my witnesses...
We as Christians never need pray these words, “Lord give me power.” The fact is that we have the power, we have all the power that we need for any situation and circumstance.
When Jesus spoke these words, He was referring to a brand new work and dispensation in the unfolding will and plan of God. You see, up until this time, men had not been indwelt by the Holy Spirit in the way that we are now. In the Old Testament, He would come upon men and women for a certain work and for a specific time. In that dispensation, man was not the temple of the Holy Spirit as he is in this dispensation. That is why David prayed in Psalm 51:11, “Take not thy Holy Spirit from me.”
Since the day of Pentecost, whenever a person receives Jesus as Savior and Lord, the Holy Spirit moves into and sets up His dwelling place in that believer, and He is there on a mission. He is not there just so you can have a goose bump experience or an exhilarating feeling, even though these are often present. He is not even there so that you can operate in spiritual gifts. Yes, these do come as part of the promise of God to man, but the main reason that He is come upon you is so that you can be His witness. Notice the rest of the verse and see the results of His coming later in the book of Acts. Those who received Him became mighty witnesses for Jesus. Yes, they operated in gifts, very powerful gifts, and signs and wonders did accompany their ministries. Yet, the reason for these was for the express purpose of witnessing for Jesus. They were done to validate and to confirm the words that the people were speaking. Notice the Bible says that their words were confirmed by signs and wonders following them.
You too have this same Holy Spirit to empower and enable you to do the works of and the ministry of Jesus, to be a witness for Him.