'Expression' in the Bible

an instructor of the ignorant, a teacher of the immature, having the full expression of knowledge and truth in the law—

The Son is the radiance of God’s glory and the exact expression of His nature, sustaining all things by His powerful word. After making purification for sins, He sat down at the right hand of the Majesty on high.

This expression, “Yet once more,” indicates the removal of what can be shaken—that is, created things—so that what is not shaken might remain.