Our spirit is sealed with the Holy Spirit (“In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise” Ephesians 1:13; KJV).
And Jesus tells us that the Holy Spirit will never leave a Jesus-believer, but stay with him or her for all eternity: “And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever” (Jesus in John 14:16; KJV)
Through the Holy Spirit in us (we do not have to feel it, we “just” have to believe what Jesus tells us) we are connected to God and Jesus and have fellowship with them forever:
“This is how we know that we live in him and he in us: He has given us of his Spirit.” (1 John 4:13; NIV).
