That is not true for we can indeed KNOW our eternal destination is with Jesus Christ.
For it is written....Jesus said...."Truly, truly, I say to you, whoever hears my word and believes him who sent me has eternal life. He does not come into judgment, but has passed from death to life." John 5:24
'I' give them eternal life, and they will 'never' perish, and 'no one' will snatch them out of my hand." John 10:28
"Because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved." Romans 10:9
There is 'therefore' now NO condemnation for those who are in Christ Jesus. Romans 8:1
All that the Father gives me will come to me, and whoever comes to me I will never cast out. John 6:37
And this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up on the last day. John 6:39
Truly, truly, I say to you, whoever believes has eternal life.John 6:47
Only God knows what is truly in the hearts of men.
One may profess belief in Jesus; whether one lives that profession truly is another question.
When I reflect on the lives of the saints, their sufferings and extraordinary commitment, I wonder: how crowded is heaven?
I am relieved when I consider that God is infinitely merciful... but I tremble that He is also infinitely just.