The following is an excerpt from J.I. Packer's powerful introduction to John Owen's classic sermon: "The Death of Death in the Death of Christ."
Also, there is a wonderful website dedicated to great theological works like this one, called Recover the Gospel. They not only have very helpful articles, but also audio and some video as well. I would highly commend them to you.
Dr. Packer's words really capture the passion of my heart in guarding the content and character of the gospel of the Lord Jesus Christ. He does a masterful job in comparing the old gospel to the new gospel. I remember reading them years ago, and they are just as powerful and stirring to me now as they were then. I pray they are just as meaningful in your hearts today.
Glory in the cross,
He saved us, not on the basis of deeds which we have done in righteousness,
but according to His mercy, by the washing of
whom He poured out upon us richly through Jesus Christ our Savior,
so that being justified by His grace we would be made heirs
according to the hope of eternal life.
by J.I. Packer
"There is no doubt that evangelicalism today is in a state of perplexity and unsettlement. In such matters as the practice of evangelism, the teaching of holiness, the building up of local church life, the pastor's dealing with souls and the exercise of discipline, there is evidence of widespread dissatisfaction with things as they are and or equally widespread uncertainty as to the road ahead. This is a complex phenomenon, to which many factors have contributed; but, if we go to the root of the matter, we shall find that these perplexities are all ultimately due to our having lost our grip on the biblical gospel. Without realizing it, we have during the past century bartered that gospel for a substitute product which, though it looks similar enough in points of detail, is as a whole a decidedly different thing. Hence our troubles; for the substitute product does not answer the ends for which the authentic gospel has in past days proved itself so mighty.
We would suggest that the reason lies in its own character and content.
It fails to make men God-centered
in their thoughts
and God-fearing in their hearts
because this is not primarily
what it is trying to do.
One way of stating the difference between it and the old gospel is to say that it is too exclusively concerned to be 'helpful' to man - to bring peace, comfort, happiness, satisfaction - and too little concerned to glorify God. The old gospel was 'helpful', too - more so, indeed, than is the new - but (so to speak) incidentally, for its first concern was always to give glory to God. It was always and essentially a proclamation of divine sovereignty in mercy and judgment, a summons to bow down and worship the mighty Lord on whom man depends for all good, both in nature and in grace. Its center of reference was unambiguously God.
But in the new gospel the center of reference is man
This is just to say that the old gospel was religious in a way that the new gospel is not. Whereas the chief aim of the old was to teach people to worship God, the concern of the new seems limited to making them feel better. The subject of the old gospel was God and his ways with men; the subject of the new is man and the help God gives him. There is a world of difference. The whole perspective and emphasis of gospel preaching has changed.
From this change of interest has sprung a change of content, for the new gospel has in effect reformulated the biblical message in the supposed interests of 'helpfulness'. Accordingly, the themes of man's natural inability to believe, of God's free election being the ultimate cause of salvation, and of Christ dying specifically for his sheep are not preached. These doctrines, it would be said, are not 'helpful'; they would drive sinners to despair, by suggesting to them that it is not in their own power to be saved through Christ. (The possibility that such despair might be salutary is not considered: it is taken for granted that it cannot be, because it is so shattering to our self-esteem.) However this may be (and we shall say more about it later),
is that part of the biblical gospel
is now preached as if it were
the whole of that gospel;
and a half-truth masquerading
as the whole truth
becomes a complete untruth.
Thus, we appeal to men as if they all had the ability to receive Christ at any time; we speak of his redeeming work as if he had made it possible for us to save ourselves by believing; we speak of God's love as if it were no more than a general willingness to receive any who will turn and trust; and we depict the Father and the Son, not as sovereignly active in drawing sinners to themselves, but as waiting in quiet impotence 'at the door of our hearts' for us to let them in.
It is undeniable that this is how we preach; perhaps this is what we really believe. But it needs to be said with emphasis that this set of twisted half-truths is something other than the biblical gospel. The Bible is against us when we preach in this way; and the fact that such preaching has become almost standard practice among us only shows how urgent it is that we should review this matter. To recover the old, authentic, biblical gospel, and to bring our preaching and practice back into line with it, is perhaps our most pressing present need."