This is a sobering verse: the refusal to hear and obey God's law does not simply mean prayers go unanswered — it means they are an abomination. God is not a vending machine to be accessed for help while His Word is ignored. Obedience and prayer are inseparable. This does not mean sinners cannot pray for forgiveness, but it does mean wilful, ongoing rejection of God's Word corrupts the very act of prayer.
Memory phrase: Obey God. Then pray.
Talk about it: Why does God want us to listen to Him before we ask Him for things?
Prayer: God, help me listen to Your Word so my prayers please You.