Everyone who dies without being reconciled to God appears before the Judgment Seat dressed so to speak in their own works and invariably there will be imperfections and sins such as separate the human being from God. In the Bible this metaphor of righteousness being like clothing is expressed in the verse “all our righteousnesses are as filthy rags” (Isaiah 64:6). Religion per se has little, if anything, to do with it.

The offered way to be reconciled to God is to accept Jesus’ death on our behalf as our only hope. We have our hearts set so as to not plead any deserving of our own but are taught that if we have believed in him and repented of our sin, He stands for us as a perfect sacrifice, and there isn’t any other such perfect sacrifice as He is both God and Man, the only bridge between us and the Father. He takes our filthy rags on Himself and gives us robes that are washed white in the Blood of the Lamb.

If you think that you are good enough to get into heaven without relying on what Jesus did, you are effectively saying to God that what Jesus did is not your plea. Effectively you are pleading innocent but without being innocent. Or, you are maybe pleading that other works you did paid for the bad things. You don’t want to see that even these good things were also done with a sinful mind, with pride and other mixed motives. And they were things you should have been doing anyway, they don’t pay anything back to God for when you failed. Only Jesus’ blood can do that. Your plea that you also did good works is not balanced out against your crimes any more than you can escape a fine for speeding by saying you had driven within the speed limit quite a lot that day. If someone stands in as the driver and takes the punishment themselves, though, then you are in the clear. They won’t offer two fines for the same infraction. In a mortal court that would be seen as perverting the course of justice, but in divine justice this is allowed because Jesus did this in love, because if not for that you had no chance to escape hell.

People in Christian churches, people convinced that they are practicing the Christian religion also need to be convinced in their hearts that they have no deserving even if they have done many good works and avoided many of the egregious behaviours of those around them. The yardstick by which you will be judged is not the pathological family you look down on at the supermarket, but the perfect righteousness of a holy God. You don’t measure up, you need to place all your reliance on Christ’s sacrifice. If you do not, then it is merely academic that you are not a Muslim, Buddhist or outright atheist. We are Christians when we have placed all of our trust in Christ alone, and been justified only by our faith in what He did on Calvary. I am not speaking here only about sacerdotal, ritualist churches, the same mentality can affect people even in the most theologically sound Evangelical churches. Salvation is between you and Jesus, has He stood in for you on Calvary? If not, then sorry, but your destiny is the same lake of fire that applies to the most benighted pagan. Jesus says “Woe unto thee, Chorazin! woe unto thee, Bethsaida! for if the mighty works, which were done in you, had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes” (Matthew 11:21).

If someone never heard about Jesus or had such a lot of lies told to them that they had no possibility to know the above truth, then God, who knows their hearts and minds better than they know themselves, is perfectly able to assess them based on what they would have done had they known this truth about Jesus. So someone who didn’t actually reject the gospel, never having heard it but who has felt in their heart that they deserve to be rejected by God unless God in love somehow forgives them, along with those who die in infancy, or are mentally unable to conceptualise these truths, most likely these people will be saved by God’s mercy. In such cases Christ’s sacrifice is imputed to them. Were this not the case then few of the Old Testament Jews would be saved either. But they knew “blessed is the man to whom the Lord imputeth not iniquity” from Psalm 32:2. Paul also reference this verse applying it to the Gospel in Romans 4:6. Paul says that this righteousness of Christ’s was available even in the times ay before He arrived on earth, much less was crucified and resurrected, for God has known all along what the solution to sin will be, even Adam was told that his seed would bruise the serpent’s head.

We cannot rely on this passive and ignorant salvation, though, whenever we have someone in front of us who doesn’t know the Gospel of Jesus Christ. Those on whom God set His seal are thirsting and dearly waiting to know the person and the work of Jesus and to hear His voice in the New Testament. So we preach like eternal life or eternal damnation depend on it, whenever we have someone before us who is seeking the truth. Those who know Jesus and have accepted Him receive a peace and assurance they lacked before. Those who have had the Gospel preached to them fully and have encountered the person of Jesus in the words of others, spoken and heard or written and read, these are without excuse and if they neglect so great a salvation, how shall they escape? Such the writer of the epistle to the Hebrews asks, in chapter 2 verse 3, and it is, of course, a very good question.

Anyone who does not accept the Gospel of Christ, having heard it, even in such a condensed form as I have given in this answer, should ask themselves that question. What other escape do you think you will find, if not the cross on which your very Creator died for you?