In the Book of Acts and the rest of the New Testament letters, people do some amazing things. They miraculously speak foreign languages without study. They raise people from the dead and heal the sick. They provide direct revelation (prophecy) from God. These gifts are known as sign gifts.
This means they’re a sign or credential the Kingdom of God has broken into this world in the person of Jesus. Something new and amazing has happened, and these miracles are signs from God proving it. It’s as if Jesus is saying, “I am God the Son. See, watch this! [Insert miracle here] Now, listen to my message …”
Jesus pointed to His miracles as proof the kingdom had come (Lk 7:21-23; cp. Isa 35:4-6). That’s why the scripture says “God also bore witness by signs and wonders and various miracles and by gifts of the Holy Spirit distributed according to his will,” (Heb 2:4). The apostles agreed (Acts 2:22), and that’s why some of them had these gifts, too (Acts 2:43).
Do these sign gifts continue, today? People have different opinions, ranging from (1) absolutely not, to (2) yes, absolutely, and (3) many shades in-between.