Matthew Poole and continuators on Psalms 139:13

13 For thou hast possessed my reins : thou hast covered me in my mothers womb.

Or, thou dost possess, thou dwellest in them, thou art the Owner and Governor of them, and therefore must needs know them. Or, thou hast formed, as some of the Ancients and others render it.

The most inward and hidden part of the body, supposed also to be the seat of mens lusts and passions.

Either, 1. with that covering called the afterbirth, wherein the infant is wrapped and preserved in the womb by the wonderful care of Divine providence. Or, 2. with skin and flesh, as it is expressed Iob 10. 11.