Machshava:

Pesach 

References: Pesachim: 7a  

Description

Why do we say a Beracha on checking Chametz? After all, we never say Berachot on staying away from prohabitions, such as, when shaving with an electric shaver, we don't say "you have commanded us...not to use a razor" or when eating kosher chicken we don't say "Blessed be you...who have commaded us...not to eat non-kosher meat"? Why then do we say a beracha on getting rid of Chametz?