"when obedience becomes our goal ,it is no longer an irritation ;instead of a stumbling block ,it becomes a building block ."
                                                    -James E.Faust 
reflection : i think James is saying that if we obey we will reach our goal.And if we don't then we will have a stumbling that we aren't sure if it would be safe to climb like a building block is . we need to be obedient . obedience is the key to success . we will do great things if we just obey . James was very smart to know this . i don't know if he lived though something in order to know this but , it made him learned something useful in life .we all need to start being obedient and choose the right . And be a CTR person. 
example: when you are disobedient you choose to go to the wrong side or to choose the wrong . And when you are obedient you choose the right .