The six-day rule is applied unevenly, which is usually a good thing.
As I understand it, this individualistic, pietistic rendering of Christian faith has only been widespread in recent centuries. The problem I have with it is that it depends on us, essentially on some perception on our part. But some people go through dark nights of the soul where God feels distant, and such a personal relationship may feel almost nonexistent. Are these struggling saints, then, less Christian?
If this is the core of Christian faith, then the earliest saints in the first decades of the Church were not Christians, because the Bible had not yet been written.
Of course, Christ would likely not be known today apart from the written record of the Bible, so in that sense it is central to the Christian faith, but one can certainly follow Jesus and be part of Christian community without intellectually assenting to American Biblical inerrantism, which is a product of modernity and not a necessary entailment of Christian discipleship. In fact, large branches of the Church, especially Roman Catholicism and Eastern Orthodoxy, see the Bible as just part of the Great Tradition, so these Christians would certainly disagree with you. (Wesleyans, though Protestant, have their own expanded version of this approach, called the Wesleyan Quadrilateral, which speaks of not one or two but four sources for theological and doctrinal development, “scripture, tradition, reason, and Christian experience.”)
I would say it is Jesus himself, as he is made known in the gospel, the good news. And what is that gospel? Some would say it is the plan of salvation, how to get to heaven, being made right with God by faith alone, etc. But this is not how the Bible itself defines the gospel. There is a reason that Mark 1:1 says that the book of Mark is itself the “gospel,” when the book of Mark does not really talk about justification by faith or saying the “sinner’s prayer.” (In fact, some would say it doesn’t even really talk much about the resurrection! NB: I didn’t finish reading the linked article and can’t endorse its contents, but I link to it just to point out that many scholars do agree that the ending of the gospel of Mark, with all its post-Resurrection appearances of Jesus, is not original.)
Mark 1:1 says that the book of Mark is the “gospel,” and the other canonical gospels are called “gospels,” because the entire story of the life and teachings of Jesus, his death and resurrection and ascension, is the gospel. The gospel — bearing in mind that this word in Roman times meant an “imperial proclamation” — is that Jesus is the King of Kings. This understanding of the “gospel” is consonant with the earliest Christian uses of the word, in the four gospels, in the sermons in the book of Acts, and in 1 Corinthians 15. (These ideas are not my own; I got them from Scot McKnight from his book The King Jesus Gospel.)
The glorious thing about this gospel is that it doesn’t require that we drum up some kind of emotional connection to Jesus that we may or may not feel, or fabricate confidence that we may or may not have that every single word written in Scripture is necessarily true in a modernistic sense. We just recognize Jesus as King, and we pledge our lives to become His disciples, with all that that entails. At the core is discipleship, or seeking to be more like Jesus, which is why Jesus calls on us to go into all the world and make disciples (not “tell people how to get to heaven”) of all nations (Matthew 28:18). It’s why Jesus calls to us,
“Come to me, all you who are weary and burdened, and I will give you rest. 29 Take my yoke upon you and learn from me, for I am gentle and humble in heart, and you will find rest for your souls. 30 For my yoke is easy and my burden is light.” (Matthew 11:18–20)
Now, of course we do believe that Jesus is alive (however we understand that) and that He answers prayer, and that God is our Father and cares about us, so absolutely we can develop that emotional relationship and it can nourish our faith; and as we read Scripture and let it speak to us (because we want to get to know Jesus and what He was / is about, more and more), we increasingly learn its truth and come to trust it; but I believe the core is this proclamation that Jesus is King and he invites our allegiance to him, and the rest flows from that. As scripture itself says (emphasis mine, and I also changed the word “Christ” to its meaning as a title, i.e., “the Anointed One”),
Consequently, you are no longer foreigners and strangers, but fellow citizens with God’s people and also members of his household, built on the foundation of the apostles and prophets, with Jesus the Anointed One himself as the chief cornerstone. In him the whole building is joined together and rises to become a holy temple in the Lord. And in him you too are being built together to become a dwelling in which God lives by his Spirit. (Ephesians 2:19–22)
Thanks for engaging with us here, Mark. You’re always welcome here.