I sware - Bengel remarks the oath of God preceded the forty years.
not - literally, “If they shall enter ... (God do so to me and more also),” 2Sa 3:35. The Greek is the same, Mar 8:12.
my rest - Canaan, primarily, their rest after wandering in the wilderness: still, even when in it, they never fully enjoyed rest; whence it followed that the threat extended farther than the exclusion of the unbelieving from the literal land of rest, and that the rest promised to the believing in its full blessedness was, and is, yet future: Psa 25:13; Psa 37:9, Psa 37:11, Psa 37:22, Psa 37:29, and Christ’s own beatitude (Mat 5:5) all accord with this, Heb 3:9.