All things work together for good to them that love God FOR WHOM HE DID FOREKNOW . . .
The reason all things work together for good to those in Christ is because God foreknew Jesus Christ. He predestinated, called, justified and glorified Jesus Christ.
Therefore, anyone placed into Jesus Christ by their faith would also be given the same things Christ was given. These are the all things that work together for good. All things that originate with man are vain. All things that originate with God work together to fulfill His eternal purpose.