Mother Teresa's letters teach that love is not something we do expecting good things in return. True love means doing things for the one you love, even when it's not easy or what we'd prefer to do. Mother Teresa had a very close relationship with Christ the first part of her life, then spent decades not hearing God's voice, and feeling empty and depressed, "like a stone." But the amazing thing is she loved and trusted God, even in these dark times. She even fell deeper in love.
This is not pretty love story, but it's one that teaches that a true love is not born of pride or jealousy or vanity. Mother Teresa's difficult walk in so many ways shows how close she was with Jesus - she truly carried a cross. Amazing.