The cross makes for discipline:
"That we may not become haughty when we acquire wealth; that we may not become proud when we receive honors; that we may not become insolent when we are blessed with prosperity and health, the Lord himself, as he deems fit, uses the cross to oppose, restrain, and subdue the arrogance of our flesh.
And he does this by various means which are useful and wholesome for each of us. For we are not all equally afflicted with the same disease or all in need of the same severe cure. This is the reason why we see different persons disciplined with different crosses. The heavenly Physician takes care of the well-being of all his patients; he gives some a milder medicine and purifies others by more shocking treatments, but he omits no one; for the whole world, without exceptions, is ill (Deut. 32:15)."