The ‘Spirit of Christ’ was in the prophets, who testified of Jesus' sufferings and the glories to follow. This includes things so remarkable that even angels desire to look into them! Peter’s masterful use of the Old Testament, whether addressing Jews or Gentiles, is eye-opening regarding the practicality and usefulness of the Old Testament to us today. Also, Peter may provide the best window into what Jesus taught about how He fulfilled the prophecies, invaluable evidence to use in persuading unbelievers.