[pinkpanther]

How are you sure only Christian go to heaven then?

His home, and the future home of all who trust in Jesus for the salvation of their soul. 

Entering into Heaven required that man’s sins be fully atoned for and that man is made perfect.  That was done for us, by Jesus, when He died on the cross to pay for our sins.  Jesus opened the way to Heaven and, when a sinner repents and trust in Jesus’ work, Jesus is faithful to forgive and to impute His righteousness (2 Cor 5:20).  It’s Jesus’ imputed righteousness (His righteousness credited to us) that makes a forgiven sinner perfect in the eyes of God.