Predictions

The future simple is used to make predictions that are based on personal judgement, opinion or intuition, and not on present evidence. Whether or not the event will happen is not certain. Such predictions are often introduced by I think / I don't think:

I don't think he'll come tonight.
I predict that Congress will pass an anti-piracy law soon.
If you ask him, he'll probably give you a lift.

In the first person, shall can be used instead of will in formal styles:

Whatever happens, we shall always be best friends.

The future simple is also used to make general predictions about facts that are always true or events that always happen:

Salty water will freeze at a lower temperature than pure water.
A gentleman will hold the door for a lady.