I would like to use these two sentences in a song, a rap song, as the last line of a verse which deals with the four elements present on the earth. My point here is that all four elements on the planet are to be enjoyed and shared among all men. Should I then say Let's have it all! Let's share it all? Or Let's have them all! Let's share them all! On the other hand, wouldn't those words sound a bit selfish and convey a contradictory intention, where I mean that men should cherish a form of togetherness? Thanks for your precious answers.
If you're talking about 4 elements right before this sentence, I would say use the plural "let's share them all" - for the flow of the rap you could say "let's share 'em all". However, "let's share it all" would be a more general statement, so it would be the better choice if you plan to use the line multiple times in the song.