For I will not dare to speak of any of those things which Christ hath not wrought by me, to make the Gentiles obedient, by word and deed, in the power of signs and wonders, in the power of the Spirit of God. So from Jerusalem even as far as Illyricum I have fully preached the gospel of Christ. – Romans 15:18-19
Paul is talking about His preaching and ministry, and what sets it apart. We know from Luke’s account in Acts that Paul was used by God to do Extraordinary Miracles. Paul doesn’t want to boast so he simply summarizes “in the power of signs and wonders, in the power of the Spirit of God.”
He was testifying on his own behalf that God was present, and you can’t deny that God was with him because of the results. Throughout the Bible, God testifies to His presence and support of the ministry and the message that someone is speaking, by showing up in power.
Can the reverse be true? If there are no miracles, no power of God, or no signs accompanying our teaching or preaching, is there something wrong, or lacking?
I remember a funny looking little prophet in my office asking me, “How many sick people have been healed by your ministry, how many demons have you cast out?” It was very humbling but also very motivating. It changed my life.