This is the fifth point we see in the subject of the Lord's Prayer: Forgiveness. Being unforgiving is the only hindrance to effective prayers as pointed out by our Lord Jesus.
If God does not forgive your trespasses, certainly your prayers cannot be answered. Many people today are prayer failures because they walk in so much unforgiving spirit and this is also the reason a lot of families are weak in prayer. When you are weak in prayer, you are weak in the power of God. When you are weak in the power of God, the devil is strong in your life and strong against you because there are so many offences in your life (there’s an extensive teaching on lack of forgiveness in my book The Danger of Offences). 
You need to get rid of the unforgiving spirit. It's a great hindrance to the fulfilment of destiny for any man on the surface of the earth. If you want to have an effective prayer life, forgive. You can practise forgiving people before they offend you. When you wake up in the morning, just say something like this, “Father, I forgive anybody that will offend me today.” 
Offences will surely come. Choose right from the beginning that you will react in forgiveness and love towards anybody that offends you. If you carry offences in your heart, it will destroy your prayer power. In fact, it shuts you up from the audience of God; it keeps you out of the hearing of God. And once God can't hear your prayer, your prayer cannot be answered. 
PRAYER: Lord, I forgive everyone that has offended me in the past. I release them genuinely from my heart today. I receive the grace to react in love towards all today in Jesus’ name. Amen!
BIBLE IN A YEAR: Numbers 11:24-13:33, Mark 14:22-52, Psalm 52:1-9, Proverbs 11:1-3