1Jn 5:6 This is the one having come by means of water and blood, Jesus the Anointed; not by the water only, but by the water and the blood; and the spirit is the one testifying, because the spirit is the truth.
1Jn 5:7 Because three are those testifying;
1Jn 5:8 the spirit, and the water, and the blood; and the three for the one are.
I know v 7 & 8 are listed as spurious passages in the "How We Got The Bible" study with a different sentence structure. Nevertheless, 1 John 5 states that the blood can testify.
Gen 9:4 But flesh with the life thereof, which is the blood..
There's life in the blood! I remember singing "There's Power (life?) In The Blood" many times while in Babylon.
Gen 4:10 And saying is the Elohim, "What have you done? The voice (life) of your brother's blood is crying (testifying) to me from the ground.
Rev 6:10 and they cried with a voice great, saying: How long, the sovereign the holy one and true one, not thou judgest and avengest the blood (life) of us from those dwelling on the earth?
Just a thought!