The most important and profound and defining experience for the disciples and the early Church is undoubtedly the Resurrection of Jesus.
It was certainly not an abstract belief or teaching but a real experience and that formed the basis for the mission of Christianity.
So the signs and wonders of the early Church were obviously not of their own making but the work of God.
And that was why, in the 1st reading, Peter said this to the people: Why are you so surprised at this? Why are you staring at us as though we had made this man walk by our own power or holiness?
That man was crippled from birth and he was healed when Peter commanded him, in the name of Jesus, to stand up and walk.
In the gospel, the Risen Jesus commissioned His disciples to go forth and preach repentance for the forgiveness of sins, and to be His witnesses.
We too have received that same commission. May we too experience the Risen Jesus and be empowered to go forth and to be His witnesses.
God will work the signs and wonders when our witnessing directs people to Him.