Yeah, Lk 1:77. I made the mistake of working from memory rather than going back and rereading the verses, which I usually do and should always do.
What I was referring to is this, the national promise:
Luk 1:71 That we should be saved[soteria] from our enemies, and from the hand of all that hate us;
Luk 1:72 To perform the mercy promised to our fathers, and to remember his holy covenant;
Luk 1:73 The oath which he sware to our father Abraham,
Luk 1:74 That he would grant unto us, that we being delivered out of the hand of our enemies might serve him without fear,
..which is not the same salvation as Lk 1:77:
Luk 1:77 To give knowledge of salvation[soteria] unto his people by the remission of their sins,
... though Lk 1:71 would not happen without Lk 1:77.
Salvation from the penalty of sin is not the same as salvation from Israel's national enemies.
Luke 1:71 is the same salvation as Luke 1:77. That isn't a mere "salvation from national enemies." Jesus didn't come to save a nation. Look forward just a little bit to verses 72 and 73 for better context:
Luke 1:70-73 KJV
(70) As he spake by the mouth of his holy prophets,
which have been since the world began:
(71) That we should be saved from our enemies, and from the hand of all that hate us;
(72)
To perform the mercy promised to our fathers, and to remember his holy covenant;
(73)
The oath which he sware to our father Abraham,
First, notice that this salvation is spoken of the holy prophets from since the world began. Not from the day of Jacob or the day of Moses but the very beginning of the world.
Second, notice that this is concerning the oath which he swore to Abraham. Paul elaborates on this further, that the seed of Abraham is a spiritual seed (and it is one seed, not two) and that the true seed of Abraham is the seed in Christ. It has nothing to do with physical bloodline.
Galatians 3:16 KJV
(16) Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
My understanding is that 'the gospel proper'(the OP) refers to how one is saved today and involves the facts which must be believed in order to place one's total trust in Christ's finished work on the cross to be justified in the sight of GOD.
That particular content has not always been required knowledge for individuals to be eternally saved.
Salvation is the free gift and grace of God, it is about faith and belief in Him. It isn't about believing facts. When you read the parable of the sheep and the goats, does Jesus separate them based on a test of certain facts? Knowledge can be
revealed and
imparted. The heart is a different matter.
During Christ's earthly ministry and for sometime in the narrative of Acts, it was only necessary for those to believe that Jesus of Nazareth was Israel's promised Messiah, the Son of GOD.
I am required to believe more than that according to the 'Gospel Proper' for today.
We are
required to believe and act upon what God reveals to us, when he reveals it to us, whenever he reveals it to us. That is included in the meaning of "faith" and "trust" and "obedience." That has always been the same and will never change..
The good news[gospel] of the Kingdom at hand is not the same as the good news[gospel] of the cross.
I don't think you understand how the gospel is accomplished, or even what is meant by it. The Kingdom at hand is the return of God on this earth and reconciling mankind to Himself once again, he brings salvation and eternal life, evil shall be no more and we shall dwell with him (and He among us.) That
is the gospel of the cross and there is no other gospel.