I am not sure of your definition. I believe that there has to be one objective truth otherwise we stand on sinking sand. (Lutheran hymn).
The Gospel, which includes the Old and New Testaments are the Gospel. The Old Testament teaches us of our sinful nature before Christ came to redeem us and the New Testament teaches us of God’s grace in and through Jesus Christ.
We can argue semantics all day. But we must recognize and accept that there is One God, One Jesus, and One Spirit.
It is interesting to note that:
I prefer the NIV version but that is not what is important. What matters is that Christ is preached. If someone is preaching him out of their own sinfulness that is OK. Someone may be listening to that does not know Scripture (most of us) but the Holy Spirit will work in him.
We are not told to win converts only to preach the Gospel. We must believe that the Holy Spirit will do his work so that Christ will be glorified.
Now comes the complex part. Do we accept Christ and are then saved?
I say no.
I say that the Holy Spirit works in us and thus we are saved through faith in Christ.
While we are still in sin we cannot accept that we need Christ and his salvation.
We cannot take credit for the work of the Holy Spirit.
Who will add to this discussion?