I've bolded and underlined the sections of what you've quoted here, so that you can more easily see it.
Yes, Christ is the true image of God...
But according to this, who is the Gospel hidden from, and why?
Think about it, JD.
This is actually a very good question, and because I am a literalist in my hermeneutics, I am going to consider context first.
Those who are lost are the Jews in this context. I can prove that.
Please bear with me because in closing this post I am going to quote quite a bit of scripture to prove what I am about to say.
One cannot read the gospels and not understand that Israel's eyes were blinded and they could not see because they failed to believe in Jesus Christ when he came to them as their Messiah. What blinded Israel. It was the parables by which he addressed them after the first 12 chapters of Matthew. This included most of his ministry to them while he lived on earth.They would never understand these parables because it takes God to reveal their truths.
You might say, God should have spoken plainly to the Jews. I say he did speak plainly to them;
John 10:24 Then came the Jews round about him, and said unto him, How long dost thou make us to doubt? If thou be the Christ, tell us plainly.
25 Jesus answered them, I told you, and ye believed not: the works that I do in my Father's name, they bear witness of me.
God spoke in parables to that generation of Jews because salvation for them nationally was now off the table.He would be dealing with individuals and giving them his truths through a spiritual means; parables.
Matt 13:15 For this people's heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes and hear with their ears, and should understand with their heart, and should be converted, and I should heal them.
16 But blessed are your eyes, for they see: and your ears, for they hear.
17 For verily I say unto you, That many prophets and righteous men have desired to see those things which ye see, and have not seen them; and to hear those things which ye hear, and have not heard them.
Here is a truth for you. Only those of Israel can be lost. Gentiles are unsaved. God has not lost them.
Paul, the apostle to the gentiles used this word "lost" one time, and you and I have been quoting it in 2 Cor 4. The context is Jews. Read all these verses following for proof;
2 Cor 3: Do we begin again to commend ourselves? or need we, as some others, epistles of commendation to you, or letters of commendation from you?
2 Ye are our epistle written in our hearts, known and read of all men:
3 Forasmuch as ye are manifestly declared to be the epistle of Christ ministered by us, written not with ink, but with the Spirit of the living God; not in tables of stone, but in fleshy tables of the heart.
4 And such trust have we through Christ to God-ward:
5 Not that we are sufficient of ourselves to think any thing as of ourselves; but our sufficiency is of God;
6 Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.
7 But if the ministration of death, written and engraven in stones, was glorious, so that the children of Israel could not stedfastly behold the face of Moses for the glory of his countenance; which glory was to be done away:
8 How shall not the ministration of the spirit be rather glorious?
9 For if the ministration of condemnation be glory, much more doth the ministration of righteousness exceed in glory.
10 For even that which was made glorious had no glory in this respect, by reason of the glory that excelleth.
11 For if that which is done away was glorious, much more that which remaineth is glorious.
12 Seeing then that we have such hope, we use great plainness of speech:
13 And not as Moses, which put a veil over his face, that the children of Israel could not stedfastly look to the end of that which is abolished:
14 But their minds were blinded: for until this day remaineth the same vail untaken away in the reading of the old testament; which vail is done away in Christ.
15 But even unto this day, when Moses is read, the vail is upon their heart.
16 Nevertheless when it shall turn to the Lord, the vail shall be taken away.
17 Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty.
18 But we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory, even as by the Spirit of the Lord.
The next word is "THEREFORE"
2 Cor 4:1 Therefore seeing we have this ministry, as we have received mercy, we faint not;
2 But have renounced the hidden things of dishonesty, not walking in craftiness, nor handling the word of God deceitfully; but by manifestation of the truth commending ourselves to every man's conscience in the sight of God.
3 But if our gospel be hid, it is hid to them that are lost:
4 In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them
5 For we preach not ourselves, but Christ Jesus the Lord; and ourselves your servants for Jesus' sake.
6 For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ.
7 But we have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us.
The pronouns are important here.