The Doctrine of Repentance by Richard Seymour explores the Hebrew and Greek meaning of the word, repentance, and considers the application intended at the time written. 

The Hebrew word (nacham) to lament and (shub) to turn away are found in Exodus 13:17; Judges 21:5-15; 1 Kings 8:47; 2 Chronicles 6:37. Sorrow or regret about sin (nachum) expressed many times by the Jews as a result of judgement. And then returning to God (shub) or turning away from disobedience to obedience.

The word repentance relating to personal salvation is only used in the new testament.

The Greek word (metanoia) to change the mind or reconsider is found in several books of the New Testament. Repentance in the Book of Acts always means repentance or change in mind about Jesus to faith in Salvation (Acts 2:38; 3:19; 17:30; 20:21).

In the epistles, Romans 2:4 says that realization of the goodness of God leads to a change of mind, repentance. 2 Corinthians 7:10 indicate regret leading to a change of attitude to Jesus. Hebrews 6:6 states it is impossible for a believer to lose his salvation and have to repent again as when he first trusted Christ.

In the book of Revelation, Jesus calls the church and the individual to repent:
Rev 2:5 repent of leaving first love by remembering, change of attitude, returning
Rev 2:21-22 change of attitude about immorality or face discipline (Gal 6:7-8)
Rev 3:19 (Rom 12:2) repentance or renewal to the right attitude
Rev 9:20-21 unwilling to change their attitude about their wicked works
Rev 16:9-11 refused to repent (change of attitude) and cursed God

God’s righteousness versus man’s righteousness:
* man seeks to do or be something to earn entrance to heaven
* God provides Salvation through Jesus Christ and it is accepted by faith alone

In Luke 13:3,5 and John 3:15,16, Jesus is teaching repentance or change of mind about the fact that all sin and are in need of Salvation (Rom 3:23-24).

Christ’s sacrifice upon the cross was sufficient for all sin and for all ages.

Failure to trust Christ brings condemnation.

More than 160 times the New Testament  says that Salvation  is by faith in Christ, not faith plus repentance or repentance followed by faith, but faith in Christ alone.

Repentance and faith are inseparable.
A change of mind toward Christ leading to faith in Salvation.

Seymour, Richard. BBN Bible Institute. The Doctrine of Repentance.   bbnradio.org

Scripture quotations are taken from the Holy Bible, New Living Translation, copyright © 1996, 2004, 2007, by Tyndale House Foundation. Used by permission of Tyndale House Publishers, Inc., Carol Stream, Illinois 60188. All rights reserved.