When John the Baptizer was sent to “prepare the way of the Lord”, he preached repentance. (John 3:1-12) According to the gospel of Mark, the first thing Jesus preached was, “The kingdom of God is near. Repent and believe the good news!” (Mark 1:14)
Jesus instructed his disciples to go to the brother who has sinned against them, show him his fault and hope he listens—or repents; if not, he outlines more steps to take. If after all that, the sinning brother still won’t listen, he is to be treated as a “pagan” (non-believer). (Matthew 18:15-17) Jesus further told them, “If your brother sins, rebuke him and if he repents, forgive him. (Luke 17:3 emphasis added) Repentance as a qualification for forgiveness is a major part of the framework of the Bible in both Old and New Testaments.
A second qualification for forgiveness is that the sin must be forgivable. Jesus said, “But whoever blasphemes against the Holy Spirit (calling the Holy Spirit’s ways evil) will never be forgiven, he is guilty of an eternal sin. (Mark 3:29, 30) John said, “There is a sin that leads to death. I am not saying that he should pray about that.” Since he didn’t specify which sin that is, I can only conclude that he referred to blasphemy against the Holy Spirit.
So no, God’s forgiveness is not “unconditional”. However, in his mercy he may occasionally grant forgiveness without repentance just as he “sends the rain on the righteous and the unrighteous”. (Matthew 5:45)
Forgiveness is often confused with God’s love. Followers of Jesus are to love each other, their neighbors, those who insult or persecute them and their enemies—that would seem to be everybody.