'Slip' in the Bible

For this reason [that is, because of God’s final revelation in His Son Jesus and because of Jesus’ superiority to the angels] we must pay much closer attention than ever to the things that we have heard, so that we do not [in any way] drift away from truth.

This hope [this confident assurance] we have as an anchor of the soul [it cannot slip and it cannot break down under whatever pressure bears upon it]—a safe and steadfast hope that enters within the veil [of the heavenly temple, that most Holy Place in which the very presence of God dwells],