Pawn Sacrifice in Middle game to activate or blockade a Bishop

In the last lessons we have seen how gambit concept works in openings: You offer a pawn for quick development. Material for time!

Today  I want to look forward into middle game. There also the pawn offer is a dangerous weapon. Especially Kasparov was known for using it! Let us start with an easy example:

 1. White sacrificed a pawn to activate his bishop 

2. Black sacrificed a pawn to make opponent`s bishop passive