Let us dig into the word "repent" which means "think differently afterwards". After we believers are born from above by the Holy Spirit (John 3:3), and in like manner given the mind of Christ (1 Corinthians 2:16). The Greek word metanoeó is the English word "repent" in Matthew 4:17. Let us obtain the definition of "repent".
Repent: think differently afterwards
metanoéō (from 3326 /metá, "changed after being with" and 3539 /noiéō, "think") – properly, "think differently after," "after a change of mind"; to repent (literally, "think differently afterwards") (def from 3340. metanoeó HELPS Word-studies section).The word "repent" does not mean "I change my mind" as asserted by too many people. Try reciting the words of Jesus, where He is commanding the people in Matthew 4:17, except, first, replace the word "repent" with "I change my mind", then, second, replace the word "repent" with "think differently afterwards". God does not change (Malachi 3:6), so this One True God Jesus commands repent.
Godly sorrow brings "thinking differently afterward" leading to salvation (2 Corinthians 7:10, so God's power generates this sorrow within the believers hence God calls it "Godly sorrow" thus illuminating and magnifying sin (Romans 5:20).
Here is the Christian teaching of 2 Corinthians 7:8-10. The passage (from the NASB which explicitly states that the NASB translators add bracketed words for clarity - so I have no problem removing the bracketed words from the NASB - but this is verbatim from the NASB):
Paul wrote a letter that exposed the Corinthian problem, see "I caused you sorrow by my letter" in verse 8.
As Paul writes further (in verse 9), the Apostle narrows the focus with "for you were made sorrowful according to God"; moreover, the Greek of ἐλυπήθητε γὰρ κατὰ Θεόν agrees with "for you were made sorrowful according to God". "ἐλυπήθητε" means "you grieved"/"you were made sorrowful", and "γὰρ" means "for", and "κατὰ" means "down"/"against"/"according to", and "Θεόν" means "God".
Paul does not leave it there, NO, rather Paul repeats himself in verse 10 to make it clear - in Jewish fashion of repeating a point for emphasis - Paul makes it clear in no uncertain terms "the sorrow that is according to God produces a repentance without regret, to salvation". That is Paul driving the Power of God exclusive role in man's salvation point home!
NOTICE THE KEYWORDS OF "ACCORDING TO GOD".
That sorrow, that repentance, is not of man's conjuring. See the keywords and absolute concept of "according to God"!
The scripture is devoid of "sorrow that is according to your free will" or "your free will to repent" or any indication about such a notion as man's free-will choice toward God.
The Apostle wrote "the sorrow that is according to God produces thinking differently afterward without regret" (2 Corinthians 7:10).
BIBLE CITATION: Or do you think lightly of the riches of His kindness and tolerance and patience, not knowing that the kindness of God leads you to repentance? (Romans 2:4).
Notice that rebuke of people that despise repentance being from God!
BIBLE CITATION: When they heard this, they quieted down and glorified God, saying, "Well then, God has granted to the Gentiles also the repentance that leads to life." (Acts 11:18)
See that God grants repentance as testified by the disciples in Acts 11:18.
BIBLE CITATION: with gentleness correcting those who are in opposition, if perhaps God may grant them repentance leading to the knowledge of the truth, (2 Timothy 2:25)
Paul testifies that God grants "thinking different afterwards" in 2 Timothy 2:25.
God grants repentance into people, as it is written; on the other hand, there is complete absence and silence in scripture for repentance as a work conjured up by man nor by man's "free will" nor "choice" nor "ability".
God grants repentance, and God acts for God's glory! Praise be to the Living God!