ויזרק means sprinkling — he sprinkled it on the people (not he threw it against the people, as this word might imply; cf. e. g., Exodus 9:8: וזרקו משה השמימה). The Targum, however, renders it by: and he poured it (the blood) upon the altar as atonement for (על) the people, adding the words “upon the altar”, and taking על העם to denote “on behalf of the people”, i. e. he poured it out to atone for the people.

First there is the command to believe in the Creator, when it says "Hear O Israel the L-ord". His intent was not for hearing of the ear, but rather for belief and acceptance of the heart, as the verse says "we will do and we will hear" (Ex. 24:7), and "Hear therefore, O Israel, and observe to do it" (Deut. 6:3), and similarly for all other verses which come in this way using a term denoting "hearing", the intent is only to bring to belief and acceptance.