Proverbs 30:5-6 → Deuteronomy 4:2

Proverbs 30:5-6 directly echoes Deuteronomy 4:2 by combining a declaration about God's word with a prohibition against adding to it. Moses commanded "you must not add to" (לֹא תֹסִפוּ, lo tosifu) God's commandments; Agur warns "do not add to His words" (אַל־תּוֹסְףְּ עַל־דְּבָרָיו, al-toseph al-devarav), using the same root יָסַף (yasaph). While Deuteronomy grounds the prohibition in covenant obedience -- keeping God's commandments without alteration -- Proverbs grounds it in the tested purity of God's speech (אִמְרַת אֱלוֹהַּ צְרוּפָה, "every word of God is refined") and adds a consequence: "lest He rebuke you and prove you a liar." The expanded range from Proverbs 30:5 ("every word of God") universalizes what Deuteronomy applied specifically to Mosaic Torah, extending the sufficiency principle to all divine revelation. Deuteronomy 4:2 in fact prohibits both directions — "you shall not add to... nor subtract from" (וְלֹא תִגְרְעוּ, velo tigre'u) — guarding the completeness of God's word against either augmentation or diminishment.