Is the church a "mixed multitude"?

Covenant theology does not draw the same Israel-church distinction. Even though there are differences between the two communities, they are basically the same in the following ways: they are both the one people of God; they experience a similar salvation experience including regeneration and the indwelling of the Spirit; their covenant signs (circumcision and baptism), though different, basically convey the same meaning; and by nature they are a “mixed” community versus a regenerate community, so that the locus of the covenant community and the locus of the elect are distinct. This latter emphasis has led to the “visible” versus “invisible” distinction, with the former referring to the “mixed” nature of the church and the latter referring to the elect throughout all ages.

We [the authors] affirm that old covenant believers were regenerated and they were saved by grace through faith in the promises of God.

The church, unlike Israel, is new because she is comprised of a regenerate, believing people rather than a “mixed” group. The true members of the new covenant community are only those who have professed that they have entered into union with Christ by repentance and faith and are partakers of all the benefits and blessings of the new covenant. This is one of the primary reasons why we argue that baptism, which is the covenant sign of the new covenant church, is reserved for only those who have entered into these glorious realities by the sovereign work of God’s grace in their lives.

P. Gentry & S. Wellum, Kingdom Through Covenant, 684-85 (cf. 72-76).

i) That’s very idealistic, but I think the authors are drawing an unstable and unsustainable distinction. They have to qualify their distinction in ways parallel to the Presbyterian position they oppose.

ii) Seems to me that NT churches are conspicuously mixed communities. In Acts and various NT letters, we see churches, which include heretics, schismatics, apostates, and impenitent sinners or backsliders.

iii) I also see a pretty direct parallel between the old covenant community and the new covenant community at a compositional level. Both religious communities are largely composed of families. Both communities contain both true believers and nominal believers.

iv) The way the authors formulate their position is equivocal. For instance, they gloss over the crucial distinction between regenerate Christians and professing Christians. Likewise, they say baptism is “reserved for only those who have entered into these glorious realities by the sovereign work of God’s grace in their lives.”

But how, for instance, do Demas, Simon Magus, Ananias and Sapphira, or Hymenaeus and Philetus fit into that framework? They were (at one time) professing baptized believers.  Were they regenerate? Were they elect? Did or didn’t they belong to the “church” and/or the new covenant community? Were they “true” members? If not, then are the authors tacitly admitting a two-tiered membership scheme?