The Christian faith is not a mere collection of doctrines — a bag of truths. Christianity is a comprehensive truth claim that encompasses every aspect of revealed doctrine, but is centered in the gospel of Jesus Christ. And, as the apostolic preaching makes clear, the gospel is the priority.
The Apostle Paul affirms this priority when he writes to the Christians in Corinth. In the opening verses of 1 Corinthians 15, Paul sets out his case:
Now I would remind you, brothers, of the gospel I preached to you, which you received, in which you stand, and by which you are being saved, if you hold fast to the word I preached to you—unless you believed in vain. For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures, and that he appeared to Cephas, then to the twelve. Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. Then he appeared to James, then to all the apostles. Last of all, as to one untimely born, he appeared also to me. For I am the least of the apostles, unworthy to be called an apostle, because I persecuted the church of God. But by the grace of God I am what I am, and his grace toward me was not in vain. On the contrary, I worked harder than any of them, though it was not I, but the grace of God that is with me. Whether then it was I or they, so we preach and so you believed.