Precious Blood
of Jesus Christ,
flow over my soul.

At Passover in the Old Testament, the blood of the lamb was smeared on the door posts of the Hebrew people as the sign for the angel of death to passover their homes.

The blood of Jesus Christ cleanses us from all sin.

I found this interesting connection when looking up the word "Messiah"
in a Jewish web site Ancient Hebrew Word Meanings
Messiah
“This word comes from the root mashahh meaning "to smear" as in Jeremiah 22:14
where it is usually translated as 'painted'.
in the ancient world olive oil was ...used as a medicine as it is a disinfectant,
no shepherd was without a flask of olive oil which he
smeared on his sheep's injuries."