Don’t miss this: the glory of God is present in the proclamation of the gospel (4:4-6)! This is why Paul is so appalled at the “peddling” (2:17) and “adulterating” (4:2) of the gospel by his opponents in Corinth. This is not a matter of mere words or a routine speech or a competitive attempt to appear more powerful or persuasive or verbally impressive than the other guy. The proclamation of the truth of the gospel is not entertainment. It is not a platform for a preacher to enhance his reputation or pad his pocketbook or impress people with his eloquence. A preacher or teacher must never open the Scriptures flippantly or casually, as if setting forth the truths of the gospel were no different from any other form of communication. The same applies anytime anyone shares the gospel with a passing stranger in a restaurant or distributes a tract to a friend. Just think of it: when you speak or write or share the message of the cross, “the light of the knowledge of the glory of God as revealed in the face of Jesus” (v. 6) is shining forth. What an awesome calling we have! What an exquisite treasure we carry (4:7)!
-Sam Storms (on 2 Cor 4:1-6)