"Every word of God is pure: he is a shield unto them that put their trust in him." (Proverbs 30:5)
When the inspired writer of Proverbs testified here that God’s Word was "pure," he did not use the usual word for, say, moral purity or metallic purity. Instead, he asserted in effect that every Word of God had been refined and purified, as it were in a spiritual furnace, so that any and all contaminants had been purged out, leaving only the pure element.
The same truth is found in the great psalm of the Scriptures (Psalm 119). "Thy word is very pure: therefore thy servant loveth it" (Psalm 119:140). David used the same word in another psalm, where it is translated "tried" in the sense of "tested for purity." "As for God, his way is perfect: the word of the LORD is tried: he is a buckler to all those that trust in him" (Psalm 18:30). The word for "buckler" in this verse is the same as for"shield" in our text. Thus God equips with a perfect shield against the weapons of any foe, because "His way is perfect" and "every word" in Scripture has been made "pure" before the Spirit of God approved its use by the human writer.
This surely tells us that the human writer of Scripture (that is, Moses or David or John or whomever), with all his human proneness to mistakes or other inadequacies, was so controlled by the Holy Spirit that whatever he actually wrote had been purged of any such deficiencies. Thus his final written text had been made perfectly "pure," free from any defects. This control applies to "every word," so that we can legitimately refer to the Scriptures as verbally inspired and inerrant throughout.
As the apostle Paul stressed, our spiritual armor in the battle against evil is "the shield of faith" and "the sword of the Spirit, which is the word of God" (Ephesians 6:16-17). HMM