1 John 3:3 - Hope and Sanctification.

And every man that hath this hope in him
purifieth himself, even as he is pure.
1 John 3:3 (KJV)

HOPE; Not a mere wish, but unshakable confidence concerning the future.
PURIFIES HIMSELF; By turning from sin. [NIV SB]

The Christian life is a process of becoming more and more like Christ.  This
process will not be complete until we see Christ face to face, but knowing
that it is our ultimate destiny should motivate us to purify ourselves. To
purify means to keep morally straight, free from the corruption of sin.
[Life Application SB]

It is true that there may be an outward correctness of deportment without
the renewing power of Christ. The love of influence and the desire for the
esteem of others may produce a well-ordered life. Self-respect may lead us
to avoid the appearance of evil. A selfish heart may perform generous
actions. By what means, then, shall we determine whose side we are on?
Who has the heart? With whom are our thoughts? Of whom do we love to
converse? Who has our warmest affections and our best energies? If we are
Christ's, our thoughts are with Him, and our sweetest thoughts are of Him.
All we have and are is consecrated to Him. We long to bear His image,
breathe His spirit, do His will, and please Him in all things.
Those who become new creatures in Christ Jesus will bring forth the fruits
of the Spirit, "love, joy, peace, long-suffering, gentleness, goodness,
faith, meekness, temperance." Galatians 5:22, 23. They will no longer
fashion themselves according to the former lusts, but by the faith of the
Son of God they will follow in His steps, reflect His character, and purify
themselves even as He is pure. The things they once hated they now love, and
the things they once loved they hate. The proud and self-assertive become
meek and lowly in heart. The vain and supercilious become serious and
unobtrusive. The drunken become sober, and the profligate pure. The vain
customs and fashions of the world are laid aside. Christians will seek not
the "outward adorning," but "the hidden man of the heart, in that which is
not corruptible, even the ornament of a meek and quiet spirit." 1 Peter 3:
3, 4.  SC58,9