Why did a relatively sizeable group (~500) of Jewish persons (~33 AD) who believed in the one God of Israel begin to worship the man, Jesus Christ?
Reading the New Testament with this question in mind leads to some really fascinating reflections. And some shocking conclusions (well: not so much for us who are Christians today, but conclusions that would have been shocking and new in the first century).
Creator, not Creature
For example, New Testament authors consistently place Jesus on the Creator side of the Creator-Creature distinction (e.g., John 1:1–3; Heb 1:2; 1 Cor 8:6; Col 1:16). Since God created and is so marked as the Creator (Gen 1, etc.), then placing Jesus, the Son of God alongside the Father as Creator signals a shared identity as Creator.
Put another way, there is an impulse to read the Gospel Books as a sort of rustic, shamble of early Jewish persons around a charismatic Jesus figure.
And yet the Gospel books were produced after most of the citations given above. The earlier theology is more elevated, more higher in terms of Christology. The earliest Christians placed Jesus on the Creator side of the Creator-creature distinction.
Theological Context of the New Testament
The Gospel Books are not then written by neutral tradents. The Gospel writers are part of a community worshipping Jesus, the resurrected man, whose identify overlaps with the God of Israel.
John makes this case clear in John 1. So does Mark in his first chapter by citing Isaiah and Malachi, passages which announce the return of YHWH but then apply that to Jesus visiting his people (Mark 1:1–3).
We Read Ourselves into the Text
I think our tendency to impute a sort of 20th-century piety, one based on simple frontier-like, homesteading faith (which is great by the way) misconstrues what the NT documents are telling us.
Jesus and the disciples were not a bunch of homesteaders or Mennonites (not a value statement but an observation). Jesus was the invisible God made manifest among us. And for that reason, in him was Life: the Life and Light of the world.
The reason why the earliest Christians worshipped the man, Jesus Christ, was because they included him in the definition of God. They may not have used a developed theological-grammar-book to dot every i and cross every t, but it is there.
When you realize that the NT writers already knew this when they wrote, then it becomes exceedingly plausible that they narrate intentionally the life of the Incarnate Word of God whose economy of salvation tells us of the deep mysteries of faith.