Sin hinders prayer. A person may pray and pray without receiving an answer, and then conclude that the problem is God. In reality the problem may be in the person’s heart. See Psalm 66:18-19.
When sin blocks prayer, the real problem is not that we have sinned but that we have not repented. It is only unconfessed sin, cherished in our hearts, that inhibits our prayers. Forgiven sin does not hinder prayer.
Not only does sin hinder prayer; prayer hinders sin. The two are always opposed. The more careless about sin, the less we will pray. The more we pray, the less careless we will be about sin.
Bot sin and prayer are powerful forces. Which one is moving you?