This concept of pleading the blood of Jesus has its roots in the Pentecostal movement.  In fact, it would probably be looked at as one of our traditions.  One of those traditions that is necessary and important in continuing to uphold. The blood of Jesus Christ is a counter agent to all that is corrupt and sinful in this world. When there is not a blood covering, sin is free to corrupt and destroy whatever it can come close to. It needs to be an active part of our praying, our singing, our worship, and our preaching . It is one of the key elements in spiritual revival.  There must be the mindset of revival always in our minds.