'Truth of the Gospel' in the Bible

But we did not yield to them even for a moment, so that the truth of the gospel would continue to remain with you [in its purity].

But when I saw that they were not being straightforward about the truth of the gospel, I told Cephas (Peter) in front of everyone, “If you, being a Jew, live [as you have been living] like a Gentile and not like a Jew, how is it that you are [now virtually] forcing the Gentiles to live like Jews [if they want to eat with you]?”

because of the [confident] hope [of experiencing that] which is reserved and waiting for you in heaven. You previously heard of this hope in the message of truth, the gospel [regarding salvation]