The first prayer after Pentecost is, “‘And now, Lord, look upon their threats, and grant to thy servants to speak thy word with all boldness, and while thou stretchest out thy hand to heal, and signs and wonders are performed through the name of thy holy servant Jesus.’ And when they had prayed, the place in which they were gathered together was shaken; and they they were all filled with the Holy Spirit and spoke the word of God with all boldness.” (Act 4:29-31)
We need the power of God. One of the reasons that God works signs and wonder is to back up the preaching of the gospel. What happened when the disciples prayed this prayer, ” The place they were gathered was shaken, and they were all filled with the Holy Spirit.”
The disciples were filled with the Holy Spirit and, “Now many signs and wonders were done among the people by the hands of the apostles. And they were all together in Solomon’s Portico. None of the rest dared join them, but the people held them in high honor. And more than ever believers were added to the Lord, multitudes both of men and women, so they even carried out the sick into the streets, and laid them on beds and pallets, that as Peter came by at least his shadow might fall on some of them. The people all gathered from the towns around Jerusalem, bringing the sick and those afflicted with unclean spirits and they were all healed.”(Act 5:12-16)
The disciples ask for a new indwelling of the Holy Spirit. So powerful was this new outpouring of the Holy Spirit that all the sick were healed by the hands of the apostles.
This is the prayer of John XXIII when he opened the Second Vatican Council.
“Divine Spirit, renew your wonders in our era as if it were by a new Pentecost, and grant that your Church, praying together, perseveringly and insistently, with one heart and mind, together with Mary, the mother of Jesus and guided by Peter, can promote the reign of the Divine Savior, the reign of justice, of love and peace.”