‘And he laid his right hand on me and said, “Do not be afraid. I am the first and the last, and the living one, I died and, see, I am alive for evermore, and I have the keys of death and of Hades”.'
Here the glorified Jesus applies to Himself the ideas previously applied to God. For ‘the first and the last' compare the Alpha and Omega of ‘the Lord God' in Revelation 1:8, and see Revelation 22:13 where both descriptions are applied to Christ; and the One Who is the first and the last and the living One parallels the One who was, and who is to come, and who is (Revelation 1:4). Compare also Isaiah 44:6 where God is said to be ‘the first and the last'. Jesus Christ is revealed to be on the divine side of reality.
‘The living One.' He is the One Who had life in the beginning, the One Who has conquered death, the One Who ever lives, and the personification of life itself. Elsewhere He could say ‘I am --- the life' (John 14:6), and as such He could give life. For even while He was on earth He could say ‘The hour --- now is when the dead will hear the voice of the Son of God, and those who hear will live' (John 5:25). How much more in the last day when ‘those who are in the tombs will hear his voice, and will come forth, those who have done good to the resurrection of life, and those who have done ill to the resurrection of condemnation' (John 5:25; John 5:28-29).
‘And I have the keys of death and of the afterworld.' It is as the Living One, Who Himself died, and burst open the gates of death and of the grave, that He has, through His eternal resurrection, received the keys of death and the afterworld so that He can release or imprison in them whom He will. Thus His people need not fear death or the grave, whatever comes, for He controls the entry and exit from both. (‘Hades' refers to the world of the dead, depicted as ‘beneath' the earth because it was associated closely with the grave whence bodies went (see Ezekiel 32:18-32). There was no thought of any real existence in it, only a shadowy form).