Hebrews 10:10

By--Greek, "In." So "in," and "through," occur in the same sentence, Pe1 1:22, "Ye have purified your souls in obeying the truth through the Spirit." Also, Pe1 1:5, in the Greek. The "in (fulfilment of) which will" (compare the use of in, Eph 1:6, "wherein [in which grace] He hath made us accepted, in the Beloved"), expresses the originating cause; "THROUGH the offering . . . of Christ," the instrumental or mediatory cause. The whole work of redemption flows from "the will" of God the Father, as the First Cause, who decreed redemption from before the foundation of the world. The "will" here (boulema) is His absolute sovereign will. His "good will" (eudokia) is a particular aspect of it. are sanctified--once for all, and as our permanent state (so the Greek). It is the finished work of Christ in having sanctified us (that is, having translated us from a state of unholy alienation into a state of consecration to God, having "no more conscience of sin," Heb 10:2) once for all and permanently, not the process of gradual sanctification, which is here referred to. the body--"prepared" for Him by the Father (Heb 10:5). As the atonement, or reconciliation, is by the blood of Christ (Lev 17:11), so our sanctification (consecration to God, holiness and eternal bliss) is by the body of Christ (Col 1:22).

— Jamieson-Fausset-Brown Commentary (public domain)