CHRISTIANITY / THEOLOGY / SALVATION
"For I do not want you to be unaware, brothers and sisters,
that our fathers were all under the cloud and all passed through the sea,
and all were baptized into Moses in the cloud and in the sea,
and all ate the same spiritual food,
and all drank the same spiritual drink.
"For they were all drinking from the spiritual rock that followed them,
and the rock was Christ.
"But God was not pleased with most of them,
for they were cut down in the wilderness.
"These things happened as examples for us,
so that we will not crave evil things as they did.
"So do not be idolaters, as some of them were.
As it is written, “The people sat down to eat and drink and rose up to play.”
And let us not be immoral, as some of them were, and 23,000 died in a single day.
And let us not put Christ to the test, as some of them did, and were destroyed by snakes.
And do not complain, as some of them did, and were killed by the destroying angel.
"These things happened to them as examples
and were written for our instruction, on whom the ends of the ages have come.
So let the one who thinks he is standing be careful that he does not fall.
"No trial has overtaken you that is not faced by others.
And God is faithful:
He will not let you be tried beyond what you are able to bear,
but with the trial will also provide a way out so that you may be able to endure it."
1 Corinthians 10: 1-13
The New English Translation
https://netbible.org/bible/1+Corinthians+10
NOTES:
The lesson here is a bit opaque, and requires one to have good knowledge of the story of the book of Exodus in the Old Testament. But the point Paul is making is this: God does judge, and he picks who gets in, and who doesn't, when it came to getting to the Holy Land. Not even Moses himself made it in!
Hence, going to heaven is not, in any way, automatic for a believer in Christ. The main idea is that your words and actions will--in fact--be judged by God, and if they do not show evidence of righteousness, then you should hold your salvation in doubt.
Back in the early centuries of Christianity, it was taught clearly that you should NEVER, EVER assume that you are going to heaven, no matter what. It was well understood that your salvation was God's decision, and it was going to be based on your whole life, not on just your core beliefs.
Hence, Paul is warning us to make sure we live in accordance with the message of the Gospel, lest we ourselves should be disqualified from ultimate salvation.
- Pseudo-Boethius