The church was meant to be a private family gathering. It was modeled on the synagogue; the public could attend, but the proceedings were aimed at the family members. The focus was to improve family life and strengthen the covenant.
In the New Testament, we see public preaching in the open square, where all such communication took place. It was necessarily evangelistic, since the preacher was appealing to outsiders only. Turning the church house into an open meeting crusade is a huge mistake. Insisting that every sermon in the church must include the logical steps of entering the Covenant of Christ is denying the family their needed encouragement within that covenant.
If the only thing you accomplish in a sermon is recounting the doctrine everyone already agrees to, don’t be surprised when spiritual growth doesn’t happen. We should be investing a lot more energy helping people tease out the implications of Biblical Law in the context of their daily lives.
The other issue we see going wrong is treating the phrase “the blood of Jesus” as if it were magic. Words do not have power; only the Holy Spirit does. Your particular points of theology are merely your logical outline of truth, not the substance of truth. Divine revelation transcends words. There is no such thing as “propositional truth” — the Hebrew prophets would sneer at such a concept. And don’t be a fool thinking they wouldn’t know what it means. They understood reason and logic; they didn’t trust the fallen mind to come to truth that way.
The vast majority of preaching in churches today wholly misses the point. The point is to take the Living Law of God — the divine moral character of Christ — and bring it to life in your context. That is not achieved by giving emphasis to the words of Scripture like some Jewish Scribe. Jesus said that was wrong. The Law of Moses wasn’t legislation with precise wording. It was an expression, a verbal manifestation of God’s divine moral character within a limited context. If the context changes, so do the words. The truth is not bound up in the words, but in a direct encounter with God on the spiritual plane.
Preaching to the congregation must assume this encounter as fundamental to moving forward in life. The preaching, like the parables of Jesus, should be virtually inexplicable without that mystical communion with the Holy Spirit. Divine revelation should be polarizing; it should divide family households when any of them are not walking the heart-led way of conviction. Thus, preaching inside the church house should raise demands that are inexplicable to outsiders. They are then challenged and this is when the Spirit draws or drives away.
We do not decide who is a good candidate for the covenant. That’s the job of the Holy Spirit. He will draw them through the impossible demands of revelation.