“Repent” is the translation of the Greek word “metanoeo” which in classical Greek meant “to change one’s mind or purpose, to change one’s opinion.” The noun “metanoia” meant “a change of mind or reflection.” These two words used in classical Greek signified a change of mind regarding anything, but when brought over into the N.T., their usage is limited to a change of mind in the religious sphere – Wuest’s Word Studies in the Greek New Testament, vol. 3, “Vocabulary”, p. 28.
Dr. Lawrence Richards in Expository Dictionary of Bible Words, page 522 states, “In the New Testament, (the Gk. words) ‘metanoeo’ and ‘metanoia’ are used in the same way as (the Heb. word) ‘sub’ in the Old Testament – to emphasize a change of mind and attitude.”
Dr. Merrill Unger in Unger’s Bible Dictionary, page 918 states, “Repentance (Gk. ‘metanoia’, means ‘a change of mind’).”
Dr. J.D. Douglas in The New Bible Dictionary, page 1084 states, “In the New Testament the terms ‘repent’ (metanoeo) and ‘repentance’ (metanoia) refer basically to a change of mind.”
That repentance means a change of thinking rather than a change of action (though a change of mind naturally leads to a change of action) can be seen from Matt. 3:8 and Acts 26:20, where repentance is differentiated from its expected result/fruit/deeds/behavior/actions.
Matt. 3:1-2, 7-10; Mk. 1:4-5, 7; Lk. 3:3-6, 15
“Repent”, here, means to change their mind/thinking/attitude from thinking that being a child/descendant of Abraham (Matt. 3:9; Lk. 3:8) will qualify them to get baptized as well as get them into the kingdom of heaven to thinking/realizing that they are sinners who are inadequate to get in without believing in the soon-to-come Messiah (Acts 19:4). And this new thinking about their sinfulness and inadequacy to get into the kingdom simply because Abraham was their father/ancestor was demonstrated by the confession of their sins (Mk. 1:5) and believing in (making ready the way of) the soon-to-come Lord/Messiah/Savior (Matt. 3:1; Mk. 1:3; Lk. 3:4; Jn. 1:25-30).
Mk. 1:15; 6:12; Matt. 4:12, 17; 11:20-23; Lk. 13:3, 5; *[Lk. 16:19-31]; Heb. 6:1; Rom. 2:4
“Repent”, here, means to change their thinking from one of trust in their own adequacy/goodness/religious works to one of trust in Jesus as the promised Messiah/Savior for entrance into His kingdom.
*[Lk. 16:30-31, Moses and the Prophets had pointed to a coming Messiah/Savior (Deut. 18:15, 18; Isa. 53; 42:1-4; 9:6-7; 61:1-3), so if Jewish people didn’t believe them, they wouldn’t change their thinking about Jesus being that Messiah/Savior even if someone rose from the dead and told them so.]
Lk. 24:46-47; Acts 26:17-20; 2 Pet. 3:9
“Repentance/repent”, here, means to change one’s thinking from whatever a person thought would gain him forgiveness for his sins to thinking that faith in Jesus Christ as Savior/God would give that person forgiveness of sins (salvation).
Acts 2:36-38; 3:14-20; 5:30-31
“Repent/repentance”, here, means to change their thinking from one of disbelief in Jesus Christ as the Messiah/Savior to one of belief in Jesus Christ as the Savior for the forgiveness of their sins.
“Repentance”, here, means a change of thinking about what saves a person and gives him eternal life (Acts 11:14, 18), and that change of thinking is that being religious won’t give one forgiveness and salvation, but believing in the Lord Jesus Christ will (Acts 10:2, 43; 11:17).
Acts 20:18-21, 24-25
“Repentance”, here, means changing their thinking from disbelief to belief in the one true God since they were idolaters (Acts 19:26-28).
“Repent”, here, means to change his thinking about the sin he committed against another person/believer, that rather than the offense being right to do, it was wrong to do, a sin.
2 Tim. 2:25
“Repentance”, here, means a change of mind from wrong thinking/believing to right thinking/believing on any biblical issue (2 Tim. 2:14, 16, 18, 23).
2 Cor. 7:9-10
“Repentance”, here, means changing their thinking about what they were doing as being wrong to thinking about the fact that they should do what was right to do.