Ifeel overwhelmingly grateful to them, but i don't know what to do with their invisible gifts. what does this quote mean?

In  the diary of anne frank, the characters feel sadness after reading the hopeful message written on the cake. which theme does this best illustrate? peace is often most appreciated after it has been lost. wartime is capable of bringing out the worst in people.  it is important to have someone in whom to confide. sharing difficult experiences can strengthen friendships