Archbishop Fulton Sheen wrote a terrific book about the good news of the gospel called Peace of Soul. He says that all men experience a natural restlessness in their hearts that can’t be pacified by indulgence in our passions. Only God can give us peace and only in Him can we rest because we are made for eternity. That is why people who don’t believe in God are in a panic to live fast and die young. Also, Mother Teresa said that the fruit of being loved is joy and the letter to the Galatians says that the fruits of the Spirit are love, joy and peace. Archbishop Sheen also says that those who deny Christ or distance themselves from Him do it to quiet their conscience by telling themselves they’re not living in their sin. Their guilty consciences can even lead them into fanatic hatred for the faith because it reminds them of their guilt and their imminent death. Here are some great quotes from the book. Archbishop Sheen is one of the greatest Catholic thinkers and he’s a 20th century American.

http://www.goodreads.com/work/quotes/1532889-peace-of-soul