What a difference following that simple rule has made in my life over the last 18 months. And what a disaster it was when I didn't know these things.
Another way to think about this concept is that in any given situation you're always following something, and that something always falls into one of two categories: God or not-God.
The one not being with Me is against Me, and the one not gathering with Me is scattering!
If you need something even less abstract, take a look at the people around you, and consider your own future, then look at your direction in all aspects of life and the decisions you make. Are they benefiting you in the here-and-now, or are they changing the future of you and your fellow human beings for the better? That is at least a step towards a better life.
But in the end, there is still this problem, that we can't understand everything that happens in the mind of man or on this Earth; we are left with either best-guessing or God-truth to rely upon. Guessing (and its frequent failure) does not appeal to me.
Is life really that black-and-white? Take it from someone who blindly stumbled around in the grey of uncertainty for some 24 years: When you want to see the difference in the colors, when you want to be able to sort truth from lies and reality from fiction, throw away your religion, your attempts to explain how we got here and why, in all of its Christian, Islamic, Buddhist, atheistic and other forms, and go find your Creator.