Acts 25:22 Then Agrippa said to Festus, “I also would like to hear the man myself.” “Tomorrow,” he said, “you shall hear him.”
I find it amazing how Paul was able to give the gospel to people in higher and higher places in the Romans society; from centurions to governors, the king and later in Rome as well.
God will use people who are willing to be used; but in doing so we need to be willing to listen to God and continue spreading the Good News.
Paul never gave up obeying God and so was used continually even though he was supposedly in captivity under house arrest.
God will open door as long as we are willing to walk through them!