I have heard this term for all my Christian life. It is usually prayed in earnest, over someone or a group for protection or a Christ covering over them of sorts, but does that make it right? I do not believe this practice is based in scripture, and no where can I find any application of anyone ‘pleading’ the blood of Christ over anyone or thing. Instead I believe It to be one of the many traditions of men that we practice in ignorance and in my opinion to be an insult to God. For we know as believers in Christ, that Jesus shed His Blood for us as He underwent the cross’s affliction and to die and be resurrected. This act was costly for it was His very life that He gave. His blood is meant for us, as individuals to receive by faith to apply it for the washing of our sins. 1 John 1:7. I cannot give His blood to anyone. I cannot cover anyone with His blood. Yet, in this expression, we – are sprinkling it around like it is some kind of thing at our disposal to use. We don’t own His blood. His blood is not to be used. His blood is to be received.
Then Jesus said to them, “Most assuredly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you. John 6:53
He who has the Son has life; he who does not have the Son of God does not have life. 1 John 5:12
For the life of the flesh is in the blood, and I have given it to you upon the altar to make atonement for your souls; for it is the blood that makes atonement for the soul.’ Lev 17:11
Therefore, brethren, having boldness to enter the Holiest by the blood of Jesus, Heb 10:19