Is it really so that only those going to heaven should partake during the memorial of Jesus Christ's death?
First off, think about Revelation chapter 7. This scripture is talking about the 144,000. Now think about it: these were taken out of the twelve tribes of Israel. So, then, there are those who are still considered of the twelve tribes of Israel. But are not part of the 144,000. Next, think about this: when Paul spoke about those partaking unworthily in 1 Corinthians 11:27, who was he talking to? Were there any of those not going to heaven involved with this statement? John, in Revelation 7:13, 14, when asked who these of the great crowd were, he didn't seem to know when he said "Lord, you are the one that knows". It doesn't seem like Paul was saying these who were unworthy of partaking were unworthy because they were not going to heaven but that they were not worthy because they had not become part of Abraham's seed in their hearts, which is what Paul was talking about in Romans 2:28, 29. Now, think about this: who of Israel were supposed to partake of the lamb of the Passover? Was it not all of them? So, since not all of spiritual Israel are part of the 144,000 and all of Israel are supposed to partake, should not all of those spiritually inclined as part of Israel partake? Now, I know what you might be thinking: Jesus concluded a covenant with those partaking (Mt 26:28). Well, think about who benefit from Jesus Christ's blood? Is it only those going to heaven? Well, consider what John 3:16 points out. Jesus' blood was for all those who exercise faith in Jesus.