Albert Barnes Commentary Psalms 119:160

"The sum of thy word is truth; And every one of thy righteous ordinances [endureth] for ever. SHIN." — Psalms 119:160 (ASV)

Thy word is true from the beginning - literally, “The head of your word is truth.” Probably the meaning is, that the “principles” of God’s word were truth, or were based on truth. The main thing—that on which all relied—was truth, absolute truth. It was not “made” truth by the mere will of God, but it was “founded on” essential truth. (Compare to Psalms 119:142, note; and Psalms 119:144, note.) Margin, “The beginning of your word is true.” Its origin is truth; its foundation is truth; its essential nature is truth. .

And every one of thy righteous judgments endureth for ever - Since any one of your laws is as certainly founded in truth as any other, it must be that all alike are eternal and unchanging. It must be so with all the essential principles of morality. Mere regulations in regard to rites and ceremonies may be altered, as local and municipal laws among people may be; but essential principles of justice cannot be. A civil corporation—the government of a city or borough—may change its regulations about streets, and culverts, and taxes; but they can never enact laws authorizing murder or theft; nor can they alter the essential nature of honesty and dishonesty, of truth and falsehood.