Some people say, "A prayer-less Christian is a powerless Christian". But power doesn't come by prayer. In the New Testament, the word "power" is frequently translated from two words, namely: "dunamis" which is the dynamic ability to cause changes and "exousia" which is authority.
Jesus refers to power in our opening verse. You received it when the Holy Spirit came into your life; you didn't get it through the effect of prayer. On the other hand, 'exousia' or authority means delegated power. The effect and the efficacy of authority depends on the power that's behind it.
We've been given authority in Christ Jesus to tread on serpents and scorpions, and over all the power (ability) of the enemy (Luke 10:19). The "power" that's behind our authority is the power of the Almighty God. This, again, didn't come by or through prayer; it was bequeathed to us in Christ as our heritage.
In Matthew 28:18, Jesus said, "...All power is given unto me in heaven and in earth". That word, "power" again is translated from the Greek word "exousia", authority. In the next verse He said, "Go ye therefore...." He delegated His authority to us immediately. Halleluiah!
It's important for us to know what we have in Christ Jesus; we have authority in His Name! We have power to effect changes and live the supernatural life every day. I would to God that Christians would know this! What impact and changes we'll make in this world!
You're fully equipped with divine power to preach the Gospel and change the world! That power is in you through the Holy Spirit.