. I agree that ' saved ' has different meanings in the context. Like ' Endure to the end to be saved ' . Just like Mathew 19 , Acts 2 .38 ect they need to be understood in context. We look to Pauls letters for how we understand salvation today . Not in the four Gospels nor in Acts . Today it should be clear that we do not ' Endure to the end to be saved " nor ' Keep the commandments and go sell everything ' . Its also not Repent , and be baptized for the remission of sins, and receive the gift of the Holy Ghost.
Clearly Eph 1 ,13-14 clashes with this . 1 cor 15 .1-4 is the Gospel . Romans 10 ,9 and Rom 1.16 explain the Gospel also . They could not be preaching the Gospel before the Gospel even happened. Acts is the transition.
Could it be that the different approach was because Israel had had 1,500 years of dealing with God and His Oracles, but that the Gentiles were coming in ice-cold? Things like homosexuality, lies, fornication, philanthropy and the like were everyday matters for the Gentile, whereas, although they were Law-breakers, the Israelites knew morals and knew prophecy. Let's take two examples.
In Acts 2 it is; "Ye men of Israel ... REPENT!" Well, repent is to change the direction you are going. Our Lord Jesus had just fulfilled 33o plus prophecies before their eyes and they called for His blood. It was not as though Jesus was unknown. He was vying for Messiah with Israel. But the Corinthians were out and out heathen and polytheists as well. The wording of the gospel would be different. But the basic message is the same, as given by the Master Himself in
Mark 16:15-16;
15 "And he said unto them, Go ye into all the world, and preach the gospel to every creature.
16 He that believeth and is baptized shall be saved; but he that believeth not shall be damned."
Matthew is different because it is not the gospel of grace that Matthew sets forth, but the gospel of the Kingdom. A man is saved SO THAT he may rule with Christ. To qualify for salvation one needs to believe. But to be found worthy of co-rulership with Christ is by how obedient you were.
Luke reveals Christ as a Man. So the gospel there is the gospel of grace - remission of sins "for all the world beginning at Jerusalem".
John deals with the remission of sins, NOT for the Kingdom like the Mark and Luke, but that men might (i) have God dwelling inside of them, (ii) that a corporate New Man might be God's House on earth, and (iii) in having the Triune God in the man, that man might be partaker of the divine life to display Christ.
Then, each of the letters addresses problems, but at the same time reveal Christ. Colossians is about the Head and His supply to His body. Ephesians is about the Body and what it is saved for. Philippians is about the personal experience of Christ to be intimate with Him ... and so on. So each mention of "saved" ties in with a specific theme. Man is made of three parts (Gen.2:7; 1st Thess.5:23), so there are at least three different "salvations" as each part has a different consistency. Then the character must be saved ... and so the spectrum of different "salvations" grows and grows.
But the foundational rule is that man could not save himself. Christ came as a worthy Man and did it by His Works. One hast to put trust in these Works to (i) be released from your sin and sins, (ii) to be reconciled to God, (iii) to be justified before God (not men), (iv) to experience a new and heavenly birth to become heirs AND have the Father's divine life to display Christ and be a "help meet" for Him. Even then, the full salvation depends on whether, after all this, you are found worthy of being a co-ruler with Christ when He sets up His Kingdom on earth when He comes.
"Salvation" is not a bedtime story. It is a vast and complex process to satisfy a 100% righteous God. Fortunately, knowledge of the whole process is not a prerequisite. Faith in a Person and His Work is.