Acts 3:11-12 (KJV)
11 And as the lame man which was healed held Peter and John, all the people ran together unto them in the porch that is called Solomon’s, greatly wondering.
12 And when Peter saw it, he answered unto the people, Ye men of Israel, why marvel ye at this? or why look ye so earnestly on us, as though by our own power or holiness we had made this man to walk?

Healing, miracles, etc. come from and are done in the name of Jesus Christ. It is by the power of the Holy Spirit working as we step out in faith and not by our own power, or godliness.
“Acts 3:6-7 (KJV) Then Peter said, Silver and gold have I none; but such as I have give I thee: In the name of Jesus Christ of Nazareth rise up and walk. [7] And he took him by the right hand, and lifted him up: and immediately his feet and ankle bones received strength.”
“Acts 3:16 (KJV) And his name through faith in his name hath made this man strong, whom ye see and know: yea, the faith which is by him hath given him this perfect soundness in the presence of you all.”

When miracles happened and the gospel is preached GOD desires people to repent. Signs and wonders are there to point to GOD and demonstrate His love in a tangible way.
“Acts 3:18-19 (KJV) But those things, which God before had shewed by the mouth of all his prophets, that Christ should suffer, he hath so fulfilled. [19] Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord;”
“Acts 3:26 (KJV) Unto you first God, having raised up his Son Jesus, sent him to bless you, in turning away every one of you from his iniquities.”

Therefore be encouraged to call on the LORD for boldness to to share the Word of God and asking GOD to perform healings, signs and wonders as we share the gospel.
“Acts 4:29-31 (KJV) And now, Lord, behold their threatenings: and grant unto thy servants, that with all boldness they may speak thy word, [30] By stretching forth thine hand to heal; and that signs and wonders may be done by the name of thy holy child Jesus. [31] And when they had prayed, the place was shaken where they were assembled together; and they were all filled with the Holy Ghost, and they spake the word of God with boldness.”