In 1 Corinthians 4:12-13, Paul speaks about the hardships and challenges faced by apostles and believers as they spread the gospel. He mentions that they work hard and endure persecution, often being treated poorly or unfairly by the world. The phrases "when we are cursed, we bless; when we are persecuted, we endure it; when we are slandered, we answer kindly" highlight the attitude of humility and love that Christians are called to maintain, even in the face of adversity.