If we apply the Hippocratic Oath to our personal lives ("first, do no harm"), it is necessary to save ourselves before we try to save the world.

This means, among other things:

Lift weights

Lose weight

Save for your own retirement

Build up a surplus of wealth (and a skill stack) so that you'll always have more opportunities than time

Once you are financially independent yourself, then and only then should you begin to worry about others.

The world doesn't need more broke 20-somethings begging for money to go on missions trips. The world needs self reliant adults who won't expect a bankrupt government to bail them out in retirement. Financial independence is a moral imperative.