II Corinthians 4 -  Paul asserts that his ministry is legitimate.. given to him by God's mercy and because of that "we do not lose heart".   Unlike others, who are preaching a false gospel, Paul has:
"renounced the things hidden because of shame"
"not walked in craftiness.." 
not  adulterated "the word of God"..
but has manifested "truth"

In other words, Paul is sticking to his plan to know nothing but Christ and Him crucified. 
Others may complain that this gospel is "veiled"... covered up.. unclear or unseen.  But, Paul says, it is only veiled to those "who are perishing", those who still live in darkness.. blinded by Satan.. unbelieving.

There is a light.. "the light of the gospel of the glory of Christ, who is the image of God. " It is Jesus Christ, the Lord.. Who had come from the Father .. " the One who has shone in our hearts to give the light of the knowledge of the glory of God in the face of Christ."  God.. the same God who was in the beginning and said "Let there be light"... speaks light into our hearts.. through Christ Jesus. 

He puts this wondrous gift of light into these "earthen vessels".. a great "treasure".. this "surpassing greatness of power" manifested in our temporal, mortal, humble souls... that He may be seen.  

Paul, when he stood before King Agrippa, spoke of the moment when this light shone into his own heart.. when Jesus stopped him on the road to Damascus with a "light from heaven, brighter than the sun.."  ( Acts 26:13)  Jesus appointed  Paul to minister to the Gentiles.. to "open their eyes so that they may turn from darkness to light and from the dominion of Satan to God, in order that they may receive forgiveness of sins and an inheritance among those who have been sanctified by faith in Me." ( v18)

Because of the Light.. Paul did not lose heart.. even when "afflicted.. perplexed... persecuted...struck down."  He carried  "in the body the dying of Jesus".. but it was so that "the life of Jesus.. may be manifested " in him too!   Paul faced death over and over again.. but he knew life.. the life of Jesus, "manifested in our mortal flesh."  Paul was absolutely confident in the resurrection power of Jesus Christ.  He was realistic about his present condition.. his "outer man" was decaying.. but he put much more weight on the truth that "our inner man is being renewed day by day".  He could therefore consider all the "momentary, light affliction" of this life.. as a tool that produced "a glory far beyond all comparison". 

We must look beyond the temporary things that we see with our earthly eyes, Paul reminds us,  and look towards the eternal, unseen things that lay ahead.

Father in heaven, holy and gracious, full of mercy and lovingkindness,  we praise Your name.  You have sent light into our hearts through the gospel of Jesus Christ, who brings forgiveness of sins and an eternal inheritance.. more glorious than we can even imagine.  Jesus, light of the world, shine on us and in us.. that the world that still lies in darkness can turn to You and be delivered from the blindness of unbelief.  I am but an earthen vessel.. You are the great treasure, the Light of the World.  Shine brightly in me, I pray, in Your Wonderful name, Jesus Christ, my Lord. Amen.