Heaven denotes fullness of being, life, goodness, truth, beauty, harmony, joy and peace and as such we can say that God is Heaven. Heaven for creatures can only mean a degree of participation in this divine life. Now the mystery of divine life begins to unfold when God's eternal Son reveals his life with Father and sent the Holy Spirit to guide us into his kingdom. He came to earth to restore Paradise Lost. For the Christian it is the moment of Baptism when the Father, Son and Holy Spirit begins to dwell in the human soul.
Most people fear death and fail to see that it is a necessary transition into the life of glory.
Woe to him who dies in mortal sin. Blessed are those who die in Your most holy will, for the second death shall have no power to do them harm.