"I don't know anything about him," says the engmatic Isabella of her lover John Gabriel just before her death. In a scene later in The Rose and the Yew Tree, Teresa, while assuring Hugh Norreys that he is not responsible for Isabella's death, says to him, "You loved her enough to leave her alone." These two bald statements are emblematic of Agatha Christie's strange yet compelling vision of life. A woman of strong views, a woman convinced that there are eternal values and verities, Christie was yet singularly free of evangelical zeal and didactic purpose. If she had a message, it was that each person should and must make choices for himself or herself and should impinge as little as possible on the choices of others. In the words of Thomas á Kempis, "You are not required to answer for others but you will have to give an account of your own life." Humility, tolerance, and acceptance are for Christie the essential virtues. She reserved her condemnation not for the sinners of the flesh, but for those who see themselves as more than other men, who use their talent to bind others to their will and their strength to kill and maim. (Afterword, p. [208], The Free Press. 1990)

The Rose and the Yew Tree in Wikipedia