The book of 1 John was written for this exact reason.
1 John 5:13 NIV
13 I write these things to you who believe in the name of the Son of
God so that you may know that you have eternal life.
Throughout the book of 1 John, the author gives many examples of how people doing things and then he tells us whether or not that person is saved. You can take all of the following tests and measure anybody against them to see which direction that, that person is going in.
Repentance is about you no longer following your own desires, but the desires of Christ for you.
2 Corinthians 13:5 NIV
Examine yourselves to see whether you are in the faith; test
yourselves. Do you not realize that Christ Jesus is in you—unless, of
course, you fail the test?
Question 1: Do you sin habitually?
1 John 5:18-20 NIV
We know that anyone born of God does not continue to sin; the one who
was born of God keeps him safe, and the evil one cannot harm him. We
know that we are children of God, and that the whole world is under
the control of the evil one.
1 John 1:6-76 NIV
If we claim to have fellowship with him yet walk in the darkness, we
lie and do not live by the truth. 7 But if we walk in the light, as he
is in the light, we have fellowship with one another, and the blood of
Jesus, his Son, purifies us from all sin.
Question 2: Do you occasionally fall short?
1 John 1:8,10 NIV
8 If we claim to be without sin, we deceive ourselves and the truth is
not in us. 10 If we claim we have not sinned, we make him out to be a
liar and his word has no place in our lives.
John 8:44 NIV
You belong to your father, the devil, and you want to carry out your
father's desire. He was a murderer from the beginning, not holding to
the truth, for there is no truth in him. When he lies, he speaks his
native language, for he is a liar and the father of lies.
Question 3: Do you confess your sins?
Psalm 32:3-6 NIV
When I kept silent, my bones wasted away through my groaning all day
long. For day and night your hand was heavy upon me; my strength was
sapped as in the heat of summer. Then I acknowledged my sin to you
and did not cover up my iniquity. I said, "I will confess my
transgressions to the LORD "—and you forgave the guilt of my sin.
1 John 1:9 NIV
If we confess our sins, he is faithful and just and will forgive us
our sins and purify us from all unrighteousness.
Romans 2:5 NIV
But because of your stubbornness and your unrepentant heart, you are
storing up wrath against yourself for the day of God's wrath, when his
righteous judgment will be revealed.
Question 4: Do you obey God?
1 John 2:4-5 NIV
The man who says, "I know him," but does not do what he commands is a
liar, and the truth is not in him. But if anyone obeys his word, God's
love is truly made complete in him.
1 John 5:3 NIV
This is love for God: to obey his commands. And his commands are not
burdensome,
2 John 1:6 NIV
And this is love: that we walk in obedience to his commands. As you
have heard from the beginning, his command is that you walk in love.
Question 5: Do you bear good fruit?
1 John 2:5-6 NIV
5 This is how we know we are in him: Whoever claims to live in him must
walk as Jesus did. 6 This is how we know we are in him: Whoever claims
to live in him must walk as Jesus did.
Question 6: Do you love your brothers?
1 John 2:9-11 NIV
Anyone who claims to be in the light but hates his brother is still in
the darkness. Whoever loves his brother lives in the light, and there
is nothing in him to make him stumble. But whoever hates his brother
is in the darkness and walks around in the darkness; he does not know
where he is going, because the darkness has blinded him.
Question 7: Do you walk in love?
2 John 1:6 NIV
And this is love: that we walk in obedience to his commands. As you
have heard from the beginning, his command is that you walk in love.
Question 8: Do you believe in Jesus?
1 John 3:23 NIV
And this is his command: to believe in the name of his Son, Jesus
Christ, and to love one another as he commanded us.
Question 9: Do you hate the things of this world?
1 John 2:15-17 NIV
Do not love the world or anything in the world. If anyone loves the
world, the love of the Father is not in him. For everything in the
world—the cravings of sinful man, the lust of his eyes and the
boasting of what he has and does—comes not from the Father but from
the world. The world and its desires pass away, but the man who does
the will of God lives forever.
Question 10: Are you persevering in repentance?
James 5:20
let him know that he who turns a sinner from the error of his way will save his soul from death and will cover a multitude of sins.
Acts 17:30
In the past God overlooked such ignorance, but now he commands all
people everywhere to repent.
Job 36:10
He makes them listen to correction and commands them to repent of
their evil.
2 Timothy 2:19
Nevertheless, God's solid foundation stands firm, sealed with this
inscription: "The Lord knows those who are his," and, "Everyone who
confesses the name of the Lord must turn away from wickedness."
Matthew 3:8
Produce fruit in keeping with repentance.
Revelation 2:19
I know your deeds, your love and faith, your service and perseverance,
and that you are now doing more than you did at first.
You will know them by their fruit.
And finally, Jesus tells us that we will know them by their fruit. The fruit that I just laid forth for you above.
Mathew 7 NIV
15 “Watch out for false prophets. They come to you in sheep’s
clothing, but inwardly they are ferocious wolves. 16 By their fruit
you will recognize them. Do people pick grapes from thornbushes, or
figs from thistles? 17 Likewise, every good tree bears good fruit, but
a bad tree bears bad fruit. 18 A good tree cannot bear bad fruit, and
a bad tree cannot bear good fruit. 19 Every tree that does not bear
good fruit is cut down and thrown into the fire. 20 Thus, by their
fruit you will recognize them.
