"And when you stand praying, if you hold anything against anyone, forgive them, so that your Father in heaven may forgive you your sins.”
Forgiving others is tough work—so much so that many people would rather do something totally distasteful than offer forgiveness to someone who has wronged them. For a person to pray while bearing a grudge, however, is like a tree sprouting leaves and bearing no fruit (11:13). True faith changes the heart. Real prayer dismantles pride and vengeance, filling the holes with love. Real faith seeks peace. For our churches to have prayer power, there must be harmony and forgiveness evident in the body of believers. Let go of hurts, abandon grudges, and forgive others.
Tyndale House Publishers. Life Application Study Bible, NIV