Hebrews 9:19

9:19 For when Moses had spoken every command to all the people according to the law, he took the blood of calves and goats with water and scarlet wool and hyssop and sprinkled both the book itself and all the people,

Hebrews 10:22

10:22 let us draw near with a sincere heart in the assurance that faith brings, because we have had our hearts sprinkled clean from an evil conscience and our bodies washed in pure water.

tn Grk “in assurance of faith.”

sn The phrase our hearts sprinkled clean from an evil conscience combines the OT imagery of the sprinkling with blood to give ritual purity with the emphasis on the interior cleansing provided by the new covenant: It is the heart that is cleansed and the conscience made perfect (cf. Heb 8:10; 9:9, 14; 10:2, 16).