In the 15th chapter of Romans, Paul notes that what has been accomplished through His ministry was done so in word and deed by the power of the Holy Spirit. Paul believed that his speaking the Gospel in obedience, Holy Spirit would manifest through signs and wonders.
He believed in the power of God.
Do we need to have faith in the power of God just as we do in His Word?
See the importance of the church today having Faith in the Power of God.