Morality without Christianity

“On the other side, morality must not be without religion, for it so, it may change as I see convenience. Religion must govern it. He that has not religion to govern his morality, is not a dram better than my mastiff-dog; so long as you stroke him, and please him, and do not pinch him, he will play with you as finely as may be, he is a very good moral mastiff; but if you hurt him, he will fly in your face, and tear out your throat.”

(John Seldon, 1584-1654, quoted by Spurgeon, commenting on Psalm 15:3-5, in The Treasury of David, 1.185)