What does Acts 4:33 mean?

Shortly before Jesus ascended into heaven, He commissioned the apostles to be His witnesses, starting in Jerusalem (Acts 1:8). To equip and empower the apostles to do so, Jesus promised the indwelling of the Holy Spirit (John 14:25–26). By this time, over five thousand men—Jews and proselytes—have responded to their witness and joined a unified body of believers (Acts 4:4).

"Testimony" is from the Greek root word martyrion and is related to the word translated "witness." The apostles testify to the fact that Jesus has risen from the dead. After He rose from the tomb, He appeared to His followers over the course of forty days; at one occasion, over five hundred saw Him (Acts 1:3; 1 Corinthians 15:5–7). This claim disturbs the Sanhedrin. The majority are Sadducees and don't believe in the resurrection from the dead. Jesus was their political and religious rival. And more and more people are being convinced that He is alive.

Initially, the Jewish leaders hesitated in destroying Jesus because they feared the people (Matthew 21:46). The Greek word translated "grace" is the same as that translated "favor" in Acts 2:47. The people incline their hearts to believe the apostles and to see them in a favorable light. The Sanhedrin's fears are coming true.