'Truth of the Gospel' in the Bible

To whom we gave place by subjection, no, not for an hour; that the truth of the gospel might continue with you.

But when I saw that they walked not uprightly according to the truth of the gospel, I said to Peter before them all, If thou, being a Jew, livest after the manner of Gentiles, and not as do the Jews, why compellest thou the Gentiles to live as do the Jews?

For the hope which is laid up for you in heaven, of which ye have heard before in the word of the truth of the gospel;