Depends on what you mean, anyone who claims to know what happens when people die is just full of shit.

We create heaven & hell right here on earth. When people get philosophy (religion) wrong it often results in extreme poverty, starvation, slavery, & mass murder. When people get philosophy right it results in lots of opportunities, fulfilling work, material abundance, & happy healthy families & communities. The problem is that these changes happen so slowly that most of the people spreading the wrong ideas are able to evade the knowledge that it was their ideas which created the problems in the first place.

The moral of the Jesus story is that, in an effort to maintain their status & authority, men will destroy the truth & everything good. They would literally kill God. And the solution is respect for individual rights (which Jesus taught), don't condemn or judge people by their group associations.

The proof of this lesson can be seen over & over throughout history. Collectivism produces unimaginable horrors, & recognition that the individual is prime produces peace & abundance.

The reason that it is always important to "aim for heaven" is that society will never become great unless there are people who are willing & able to create things that will outlast them. "Aim for heaven" is just a different way to say "lower your time preference."