" When obedience becomes our goal , its no longer an irritation , ; instead of a stumbling block , its becomes a building block " . - James E. Faust . 

What James E. Faust is trying to refer that when your obedience you wont need to worry about something else . Obedience is only stumbling blocks when you chose not to obey . But if you chose to obey , its going to become like building a block . You wont longer worry about the the bad because you know that you chose the right thing to do . This will become more like a habit and it wont no longer become an irritation .