Well...
The bible is certainly open to interpretation. One can find justification for any course of action and even justification for bashing out the brains of children and eating them, in it. If a person hears a voice in their head telling them to murder others, they can justify it as God telling them to do it. And many have done just that.
Just what the teaching was is not possible to know with certainty. It wasn't written by Jesus, or if it was, the original manuscripts were destroyed. We do know that he could read and write.
The disciples also didn't write his teachings down or there again, their versions were destroyed. What did finally get included in the bible was what was acceptable, delectable, pleasing, to the Romans.
The first council of Nicaea, A.D. 325 commissioned by the Emperor Constantine, who had a dream that he could rule the people with this religion, and who remained a sun-worshiper until the day he died, rejected those documents that weren't pleasing to Romans and gave us a collection that more or less is what became the Bible.
They incorporated Oester into the new religion as its primary holiday.
Wikipedia describes the main disagreement at that council
'the presbyter Arius argued for the supremacy of God the Father, and maintained that the Son of God was created as an act of the Father's will, and therefore that the Son was a creature made by God, begotten directly of the infinite, eternal God. Arius's argument was that the Son was God's very first production, before all ages. The position being that the Son had a beginning, and that only the Father has no beginning. And Arius argued that everything else was created through the Son. Thus, said the Arians, only the Son was directly created and begotten of God; and therefore there was a time that He had no existence. Arius believed that the Son of God was capable of His own free will of right and wrong, and that "were He in the truest sense a son, He must have come after the Father, therefore the time obviously was when He was not, and hence He was a finite being",[39] and that He was under God the Father. Therefore, Arius insisted that the Father's divinity was greater than the Son's. The Arians appealed to Scripture, quoting biblical statements such as "the Father is greater than I",[40] and also that the Son is "firstborn of all creation".'
So the Christians who ultimately prevailed, also disliked those who quoted scripture, Carpathianpeasant.
The teaching can only be known through the scriptures, and since the teaching is far more important than the person, there is value in being precise in stating it.
As for myself, I reject all of its teachings as being inadequate for people today.
Constantine declared Sunday the day of rest in honor of his Sun god.
"In 331 Constantine commissioned fifty Bibles for the Church of Constantinople, but little else is known (in fact, it is not even certain whether his request was for fifty copies of the entire Old and New Testaments, only the New Testament, or merely the Gospels), but some scholars believe that this request provided motivation for canon lists. In Jerome's Prologue to Judith[68] he claims that the Book of Judith was "found by the Nicene Council to have been counted among the number of the Sacred Scriptures", which suggests that the Nicene Council did discuss what documents would number among the sacred scriptures."
As for Christmas, Jesus was likely born in the spring.
"When church officials settled on December 25 at the end of the third century, they likely wanted the date to coincide with existing pagan festivals honoring Saturn (the Roman god of agriculture) and Mithra (the Persian god of light). That way, it became easier to convince Rome’s pagan subjects to accept Christianity as the empire’s official religion."