In these passages are the accounts of Peter healing a paralyzed man and raising a dead woman back to life. As a result of these miraculous acts, many people came to believe in Jesus.
Before Jesus was crucified, He performed many miracles to convince people that He was the Son of God, the Christ. Many came to believe in Him as a result. The miracles gave credibility to the message.
We do not need miracles today to believe. We have the Word of God, the Bible. Interestingly, the Bible must first be believed before it can be understood.