Luke 20:18 - Born Again or Lost Forever?

Whosoever shall fall upon that stone
shall be broken;
but on whomsoever it shall fall,
it will grind him to powder.
Luke 20:18 (KJV)

The "cornerstone" was either the key stone in the foundation, on
which a structure rests, or the key stone in an arch, which binds the
structure together. Each image beautifully reflects the role of Christ in
God's plan of salvation. Everything rests on Him, and He holds all
things together. Those who launch themselves against this stone will be
crushed, along with all their hopes. [Victor Bible Reader's Companion]

To those who believe, Christ is the sure foundation. These are
they who fall upon the Rock and are broken. Submission to Christ and
faith in Him are here represented. To fall upon the Rock and be broken
is to give up our self-righteousness and to go to Christ with the
humility of a child, repenting of our transgressions, and believing in
His forgiving love. And so also it is by faith and obedience that we
build on Christ as our foundation..... And on "whomsoever it shall fall,
it will grind him to powder." The people who rejected Christ were
soon to see their city and their nation destroyed. Their glory would
be broken, and scattered as the dust before the wind..... So it will
be in the great final day, when judgment shall fall upon the
rejecters of God's grace. Christ, their rock of offense, will then appear
to them as an avenging mountain. The glory of His countenance,
which to the righteous is life, will be to the wicked a consuming
fire. Because of love rejected, grace despised, the sinner will be
destroyed. DA599-600

How many resemble the Jews who murdered the prophets and
crucified Christ, in their enmity to God, and aversion to his service,
desiring to live according to their lusts, without control!.... Awful will
be the doom, both of those who reject the Son, and of those who
profess to reverence Him, yet render not the fruits in due season.... It
is the folly of sinners, that they persevere in sinful ways, though
they dread the destruction at the end of those ways. [Matthew Henry
Commentary]

Have you fallen upon the Rock, Christ Jesus, or are you waiting
to be crushed by His second coming?  Have you given Him your old
life of sin with its selfish and rebellious nature; replacing it with
His peace that passeth all understanding?  Have you turned from your
life of passion, greed and pride and accepted His life of caring
service to the hurting, the lonely and needy (1Jo.2:16; Mat.25:35)?
Have you exchanged your sexual immorality, impurity and debauchery;
idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish
ambition, dissensions, factions and envy; drunkenness, orgies, and the
like for His love, joy, peace, patience, kindness, goodness,
faithfulness, gentleness and self-control (Gal.5:19-23)?  Have you been
crucified with Christ nevertheless you live; yet not you, but Christ
liveth in you: and the life which you now live in the flesh you live by
the faith of the Son of God, who loved you, and gave himself for you
(Gal.2:20).  Are you denying the things of the old man of sin and following
after the ways of Jesus (Luk.9:23)?  Are you no longer living unto
yourself but unto him who died for you, and rose again (2Co.5:15).  If
not, Why not?  And, if not, is it really worth the loss of eternity?