While it goes without saying that there are at least two Gospels (or Evangels) in Scripture (and please read this article if you aren’t aware of this fact already), some people might ask why there are two Gospels in the first place, and why Jesus didn’t preach the same Gospel during His earthly ministry that Paul later preached to the nations. Well, the answer to that question is simply that He couldn’t, because if He had, nobody would be able to get saved (at least not in the manner of salvation that Paul generally referred to, which was being made immortal, and hence sinless, not to mention being justified in the manner that Paul referred to). You see, as we’ve already learned, the Gospel Paul preached is Christ’s death for our sins, entombment, and resurrection, and this event is the very basis of our salvation (and is, in fact, the only reason anyone can be saved when it comes to the type of salvation Paul primarily taught about). This means that if Jesus had preached the same message (that His death was going to be for our sins, meaning that His death would be the basis of our salvation) as His Gospel around Israel before He died, the spiritual powers of darkness behind His death would have undoubtedly heard and learned the truth and would not have Him crucified after all (and, in fact, would have done what they could to keep Him from dying, since they don’t want humans being made immortal and sinless). Yes, humans technically killed Jesus, but it was the evil spiritual beings ruling the world behind the scenes during this eon who drove them to it, but only because they thought it would put an end to His eventual usurping of their leadership. Little did they realize that they were played, since His death was the main reason He was born in the first place, but that fact was well disguised by His ministry to the Circumcision (in fact, that’s likely a large part of why God had a chosen people in the first place: basically, God plays the long game).
This is the same reason, by the way, that Jesus didn’t preach the salvation of all humanity during His earthly ministry either. Simply put, Jesus couldn’t have preached the salvation of all humanity, because His death for our sins (and subsequent entombment and resurrection) is the basis for the salvation of all humanity, and had He taught the salvation of all humanity publicly during His earthly ministry, the spiritual powers of darkness would have almost certainly put two-and-two together and realized that Him dying for our sins and God raising Him would be the only possible way that all humanity could be made immortal (these are highly intelligent beings, after all), and they would have then avoided their plan to have Him killed, resulting in nobody being saved at all.