Charles H. Spurgeon on Psalms 119:69

The proud have forged a lie against me. They first derided him (Psalms 119:51), then defrauded him (Psalms 119:61), and now they have defamed him. To injure his character they resorted to falsehood, for they could find nothing against him if they spoke the truth. They forged a lie as a blacksmith beats out a weapon of iron, or they counterfeited the truth as men forge false coin. The original may suggest a common expression "They have patched up a lie against me." They were not too proud to lie. Pride is a lie, and when a proud man utters lies "he speaketh of his own." Proud men are usually the bitterest opponents of the righteous: they are envious of their good fame and are eager to ruin it. Slander is a cheap and handy weapon if the object is the destruction of a gracious reputation; and when many proud ones conspire to concoct, exaggerate, and spread abroad a malicious falsehood, they generally succeed in wounding their victim, and it is no fault of theirs if they do not kill him outright. O the venom which lies under the tongue of a liar! Many a happy life has been embittered by it, and many a good repute has been poisoned as with the deadliest drug. It is painful to the last degree to hear unscrupulous men hammering away at the devil's anvil forging a new calumny; the only help against it is the sweet promise, "No weapon that is formed against thee shall prosper, and every tongue that riseth against thee in judgment thou shalt condemn."

But I will keep thy precepts with my whole heart. My one anxiety shall be to mind my own business and stick to the commandments of the Lord. If the mud which is thrown at us does not blind our eyes or bruise our integrity it will do us little harm. If we keep the precepts, the precepts will keep us in the day of contumely and slander. David renews his resolve "I will keep"; he takes a new look at the commands, and sees them to be really the Lord's "thy precepts"; and he arouses his entire nature to the work "with my whole heart." When slanders drive us to more resolute and careful obedience they work our lasting good; falsehood hurled against us may be made to promote our fidelity to the truth, and the malice of men may increase our love to God. If we try to answer lies by our words we may be beaten in the battle; but a holy life is an unanswerable refutation of all calumnies. Spite is balked if we persevere in holiness despite all opposition.