"All who are led by the Spirit of God are sons of God."
Romans 8:14
Holiness is necessary for our assurance of salvation—not at the
moment of salvation, but over the course of our lives. True faith will always
show itself by its fruits. "If anyone is in Christ, he is a new
creation" (2 Corinthians 5:17).
I recall a young man, a fairly new Christian, whose father was
visiting him. He hadn't seen his father for several years and not since he'd
become a Christian. He was eager to share his newfound faith with his dad, and
we prayed together that he might be an effective witness to his father.
Afterward I asked him how it had gone with his witness. He told
me his dad claimed to have trusted Christ as his savior when he "went
forward" at age ten in an evangelistic meeting. I asked the young man,
"In all the years you were growing up, did you ever see any evidence your
father was a Christian?" His answer was "no." What reason have
we to put confidence in that man's salvation? He was almost sixty and had never
once given his son any evidence that he was a Christian.
The only safe evidence that we're in Christ is a holy life. John
said everyone who has within him the hope of eternal life purifies himself just
as Christ is pure (1 John 3:3). If we know nothing of holiness, we may flatter
ourselves that we're Christians, but we don't have the Holy Spirit dwelling
within us.
Everyone who professes to be a Christian should ask himself,
"Is there evidence of practical holiness in my life? Do I desire and
strive after holiness? Do I grieve over my lack of it and earnestly seek God's
help to be holy?" (Excerpt taken from The Pursuit of Holiness)