First, the line of progress is never straight. For a period a movement may follow a straight line and then it encounters obstacles and the path bends… - Martin Luther King Jr.

I am convinced that love is the most durable power in the world. It is not an expression of impractical idealism, but of practical realism. Far from being the pious injunction of a Utopian dreamer, love is an absolute necessity for the survival of our civilization. To return hate for hate does nothing but intensify the existence of evil in the universe. Someone must have sense enough and morality enough to cut off the chain of hate and evil, and this can only be done through love.” — Martin Luther King Jr.

Merit is a work for the sake of which Christ gives rewards. But no such work is to be found, for Christ gives by promise. Just as if a prince should say to me, "Come to me in my castle, and I will give you a hundred florins." I do a work, certainly, in going to the castle, but the gift is not given me as the reward of my work in going, but because the prince promised it to me.

The First Sermon on the Day of the Visitation of Mary (Die erste Predigt am Tag der Heimsuchung Mariä). (1532).