The following is an excerpt from The MacArthur New Testament Commentary on Acts 2.

and many wonders and signs were taking place through the apostles. (2:43b)

One reason for the awe the first fellowship inspired was the many wonders and signs performed by the apostles (cf. Mark 16:20; Heb. 2:4). Some of those miracles are described in the succeeding chapters (cf. 3:1–10; 5:12, 15–16; 9:32–35, 40–42). As noted in the discussion of Acts 2:22 in chapter 5, wonders and signs were designed to attract attention and point to spiritual truth. The response to Peter’s healing of the paralyzed man in Lydda (Acts 9:32–34) shows that purpose clearly. The people of that region, after witnessing the healing, “turned to the Lord” (Acts 9:35). Peter’s raising of Dorcas elicited the same response in Joppa (Acts 9:42).

Our Lord did His miracles for the same reason. In John 14:10–12 He said,

Do you not believe that I am in the Father, and the Father is in Me? The words that I say to you I do not speak on My own initiative, but the Father abiding in Me does His works. Believe Me that I am in the Father, and the Father in Me; otherwise believe on account of the works themselves. Truly, truly, I say to you, he who believes in Me, the works that I do shall he do also; and greater works than these shall he do; because I go to the Father.

The ability to perform miracles was not given to all, but was limited to the apostles and their close associates (Such as Philip; cf. Acts 8:13). The writer of Hebrews said,

How shall we escape if we neglect so great a salvation? After it was at the first spoken through the Lord, it was confirmed to us by those who heard, God also bearing witness with them, both by signs and wonders and by various miracles and by gifts of the Holy Spirit according to His own will. (Heb. 2:3–4; cf. 2 Cor. 12:12)

God attended the preaching of the apostles with miracles to confirm that they were indeed His messengers. With the passing of the apostolic age, and the completion of the canon of Scripture, the need for such confirmatory signs ended. Today we can determine who speaks for God by comparing their teaching with God’s revelation in Scripture.

Although the sign gift of miracles is no longer extant, God still performs miracles in response to the prayers of His people. They are not, however, public signs like those in the apostolic era. The greatest of all miracles God performs today is the transformation of rebellious sinners into His beloved children, who are becoming like His Son. Such miracles occur in the life of the church that is committed to the fulfillment of its spiritual duties.