2 Corinthians 5:5-6
5 • He who has prepared us for this very thing is God,
• who has given us the Spirit as a guarantee.
6 So we are always of good courage.
• We know that while we are at home in the body
we are away from the Lord,
To explain the 'this very thing' of verse 5 we ought to expand it with words from verse 4 to: 'He who has prepared us for [what is mortal being swallowed up by life] is God.' It is God the Father who has prepared us for the mortal being swallowed up by life — or in less expressive language — he has prepared us for the life of heaven after we die.
The Father prepares us for heaven in three ways:
• He adopts us into his family so that we have a title to go there.
• He gives us his Holy Spirit now, not only as a guarantee — 'guarantee' doesn't convey the whole meaning — but as an earnest to encourage us. An earnest is more than a guarantee because a guarantee can simply be a token whereas an earnest is a down payment of what is guaranteed. When the Spirit is given as an earnest of our inheritance [Ephesians 1:14] it is because God is our full inheritance so the Spirit given now as an earnest of the life we will live in heaven enables us to anticipate without anxiety life without the body in the intermediate state.
• He retains his Son in heaven preparing a place for us [John 14:2] so that we no longer feel fully at home in the body and look to be at home where Jesus is and to go home to there.