Here is something regarding Heb. 4:12 I would like for you the reader to theologically ponder...

When we analytically look at this particular Heb. 4:12 Passage we see that the soul is distinctive from the spirit and that the joint is equally distinctive from the marrow. As such, in Heb. 4:12 apostle Paul laid down literal penetration markers (soul-spirit separator and joints separator - the marrow) as to what degree the quick and sharp power of the WORD was capable of piercing into.

Moreover, when looking at the soul-spirit relationship they are revealed to be divided by the Greek noun merismos (separation i.e. a separator).

However, when we look at the comparative joint-marrow there is no implied separator if we suggest that the marrow is defined to be the literal bone marrow, and as per this suggested analysis the marrow (bone) would then be completely enclosed within the stated joint (bone) itself.

Therefore, by comparative analysis this would then imply that the spirit would be completely enclosed by the soul, i.e. the figurative circle within the circle.

However, this suggested construct of Heb. 4:12 seems somewhat problematic in regards to apostle Paul in 2 Cor. 6:16, et al., where he declared that "Ye are the Temple of the Living God..." implying that the physical structural Temple of God under the Mosaic Law has now been replaced by the mortal human body as the symbolic Temple of the Living God in respect to the New Covenant of Grace.

Therefore, seeing then that the Temple of God under the Mosaic Law and the Temple of God under the New Covenant of Grace are both trichotomous, then by direct comparative analysis the Mosaic Temple of God consisted of the physical structure itself which enclosed the Holy Place, then the Veil of Separation, and then the Holy of Holies (most Holy Place).

Moreover, if we look at the actual Greek text (TR) of 1 Thess. 5:23 we find that the spirit, soul, body are each preceded grammatically by the Greek definite article THE and separated by the Greek conjunction kai. Thus, we have THE spirit and THE soul and THE body. As such, we have a trichotomously designed man.

To this end, 1 Thess. 5:23 and Heb. 4:12 then reveal the literal markers that are penetrated by the powerful WORD, hence Body-Soul-Spirit to the innermost markers of the Greek "merismos" and "myleos" (separators).

Thus, it is only logical then that there must be some literal entities for the quick and sharp WORD to penetrate. You cannot plunge a figurative sharp knife into nothingness — there must be a marker(s).

However, the Holy Place and the Holy of Holies which were separated by the Veil were LINEAR.

Thus, the Holy of Holies was not completely enclosed by the Holy Place but as stated they were linear, i.e., NOT a figurative circle within a circle.

To this end, please note that apostle Paul in Heb. 4:12 did not say to the bone and marrow but rather to the joint and marrow, and as we all know a joint is where two objects (bones) are joined together, just as the comparative soul and spirit are suggested to be joined together but divided by a separator.

Therefore, it can be suggested that the marrow (equally defined as the innermost part, etc.) is the SEPARATOR (i.e. figurative cartilage) between the joints like the separator of the soul and spirit, but they are LINEAR and not a figurative circle within a circle.

I said all of the above to suggest that the spirit is not completely enclosed and encapsulated by the soul but rather each is independent of the other and divided by an innermost separator. Hence, they are linear.