When he had said this, Jesus called in a loud voice, “Lazarus, come out!”
Why did Jesus use a loud voice to command Lazarus? Was it because Lazarus was in the tomb and volume was needed for him to hear Jesus? No, it was for the benefit of the crowd, so that they would know for certain that it was at the command of Jesus and by the power of God that Lazarus was raised from the dead, and not by a muttered magical spell.
It has been said that it was a good thing that Jesus called Lazarus by name or else all of the dead would have risen from their graves as they will when He comes again (John 5:28,29; 1 Th 4:16).
John 5:28-29 “Do not be amazed at this, for a time is coming when all who are in their graves will hear his voice and come out—those who have done good will rise to live, and those who have done evil will rise to be condemned.
1 Thessalonians 4:16 For the Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first.