'In the world they call cows and horses, elephants and gold, slaves, wives, fields and houses greatness. I do not mean this,' thus he spoke; 'for in that case one being (the possessor) rests in something else, (but the Infinite cannot rest in something different from itself.)

In plain words: Sanatkumara explains that he does not mean greatness the way people usually mean it. Cattle, gold, servants, family, land and houses are called greatness, but then the owner depends on something outside himself. The Infinite depends on nothing else.