Repentance in the Bible

In a biblical context, repentance is recognizing that our sin is offensive to God. Repentance can be shallow, such as the remorse we feel because of fear of punishment (like Cain) or it can be deep, such as realizing how much our sins cost Jesus Christ and how his saving grace washes us clean (like the conversion of Paul).
Calls for repentance are found throughout the Old Testament, such as Ezekiel 18:30:
“Therefore, O house of Israel, I will judge you, each one according to his ways, declares the Sovereign LORD. Repent! Turn away from all your offenses; then sin will not be your downfall.” (NIV)
This prophetic call for repentance is a loving cry for men and women to return to dependence on God:
“Come, let us return to the LORD; for he has torn us, that he may heal us; he has struck us down, and he will bind us up.” (Hosea 6:1, ESV)
Before Jesus began his earthly ministry, John the Baptist preached:
“Repent, for the kingdom of heaven is at hand.” (Matthew 3:2, ESV)
Jesus also called for repentance:
“The time has come,” Jesus said. “The kingdom of God is near. Repent and believe the good news!” (Mark 1:15, NIV)