Helpful words of encouragement for a friend include Calvin Coolidge's encouragement to "Press on — nothing can take the place of persistence" and Helen Keller's words that character develops through trials. Another helpful word of encouragement is that a situation changes at the time when the situation seems helpless.
Coolidge goes on to say that nothing replaces persistence. Without continuing through a challenging situation with determination, a person cannot realize her true talent. Coolidge says that education and genius are meaningless without persistence.
Keller says that suffering strengthens the soul. She says that challenges lead to success and inspire ambition. Keller also says that a person must live life with its challenges in order to understand life. Likewise, Harriet Beecher Stowe says that it is most important not to give up at the time when a person feels like she cannot hang on any longer because the moment of desperation is when the person's situation improves.