The essence of a thing is what it boils down to. We might ask, what is the core of it?
Many say the core of Christianity is right living, living the Way of God as taught by Jesus, and not right believing.
Reading the Gospels, I find many examples of what that kind of living entails. It is inclusive, the rain falls on us all. It is forgiving, as the story of the prodigal son. It is generous hearted, as not judging by appearances. There are examples after examples of what Jesus considered to be right living. There are very few about right believing. Re-read them yourself and check this out.
There are many examples of faith in God. Jesus even directed that faith away from himself, as "it is not I, but the Father within doing the work." Also, his prayers, and examples of prayers we should pray, are directed to God, not to himself.
His first followers experienced the Presence of God in the presence of Jesus, and so simply had to follow his Way. His Way was irresistible to those who had eyes to see and ears to hear. And not all had those eyes and ears, such as the Romans, with a couple of exceptions, and much of the temple leadership. Since we cannot experience all the same as the disciples, we can begin to walk The Way by living as he taught, by right living. That will lead us into a deeper walk where spiritual understanding opens and opens and opens.
May God bless our walk upon His path and lead us ever onward, enfolded in Love. Open our core to Your Essence blessed One.