What does it mean to repent of sin?

Webster's dictionary of New World College defines repentance as "a repentance or a penitent; feeling of displeasure, especially for making a mistake; compulsion; contrition; remorse". Repentance is also known as a change of mentality, going away, returning to God, turning away from sin.

Repentance in Christianity means a sincere departure, both in mind and heart, from oneself to God. It implies a change of mentality that leads to action: detachment from God towards a sinful path.

The Biblical Dictionary Eerdmans defines repentance in its fullest sense as "a complete change of orientation which implies a judgment on the past and a deliberate redirection for the future".

Repentance in the Bible
In a biblical context, repentance is recognizing that our sin is offensive to God. Repentance can be superficial, like the remorse we feel because of fear of punishment (like Cain) or it can be profound, like understanding how much our sins to Jesus Christ and how his saving grace washes us purely (like Paul's conversion).

Requests for repentance are found throughout the Old Testament, such as Ezekiel 18:30:

“Therefore, O house of Israel, I will judge you, each according to his ways, declares the Sovereign Lord. Repent! Get away from all your offenses; then sin will not be your downfall. " (NIV)
This prophetic call to repentance is a loving cry for men and women to return to dependence on God:

“Come, let's go back to the Lord, because he tore us away, to heal us; it brought us down and will bind us. " (Hosea 6: 1, ESV)

Before Jesus began his earthly ministry, John the Baptist preached:

"Repent, because the kingdom of heaven is near." (Matthew 3: 2, ESV)
Jesus also asked for repentance:

"The time has come," said Jesus. "The kingdom of God is near. Repent and believe the good news! " (Mark 1:15, NIV)
After the resurrection, the apostles continued to call sinners to repentance. Here in Acts 3: 19-21, Peter preached to the unsaved men of Israel:

"Repent therefore, and go back, so that your sins can be canceled, that the times of refreshment can come from the presence of the Lord, and that he can send the Christ appointed for you, Jesus, whom heaven must receive until the time for restoring all the things that God spoke about by the mouth of his holy prophets long ago. "(ESV)
Repentance and salvation
Repentance is an essential part of salvation, which requires a departure from the life governed by sin towards a life characterized by obedience to God. The Holy Spirit leads a person to repent, but repentance itself cannot be seen as a "good work" that adds up to our salvation.

The Bible states that people are saved only by faith (Ephesians 2: 8-9). However, there can be no faith in Christ without repentance and no repentance without faith. The two are inseparable.