Charles H. Spurgeon on Psalms 15:3

Despise not thy neighbour, but think thyself as bad a sinner, and that the like defects may befall thee. If thou canst not excuse his doing, excuse his intent which may be good; or if the deed be evil, think it was done of ignorance; if thou canst no way excuse him, think some great temptation befell him, and that thou shouldst be worse if the like temptation befell thee; and give God thanks that the like as yet hath not befallen thee. Despise not a man being a sinner, for though he be evil to-day, he may turn to-morrow. William Perkins, 1558-1602.

Verses 3, 4, 5. They that cry down moral honesty, cry down that which is a great part of religion, my duty towards God, and my duty towards man. What care I to see a man run after a sermon, if he cozens and cheats as soon as he comes home? On the other side, morality must not be without religion, for if 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.