Illustrate a respectful and devotional watercolor representation of the spiritual concept as described in the biblical verses of Matthew 6:14-15. The artwork should depict themes of forgiveness, divinity, and the act of sinning, showing the contrast between forgiving and not forgiving. The setting can be a serene, heavenly space using soft, pastel colors for a tranquil and peaceful effect, embodying the essence of the message. Do not incorporate any text or words within the image. Remember, the purpose is to communicate the Christian values through the visual language of the painting.