How Important is Blood to God?

Curiosity can motivate one's desire to pursue knowledge of something that was commonly expressed, but was not sufficient to form a conclusion. Christians generally used the phrase, " there is power in the blood." Sometimes they express the term, "we plea the blood." I became curious about the above phrases, and wanted to know if there were any value to these phrases, and also wanted to know the origin of the idea of those phrases. I asked myself the question, who promoted the idea that there was power in the blood? And, where did the idea of "we plea the blood" originated. If you were like me, where would you find your answers to those well-deserved questions? You can by now, if you have read this book carefully.