וַיֹּ֣אמֶר יְהוָה֮ אֶל־מֹשֶׁ֣ה וְאֶֽל־אַהֲרֹן֒ קְח֤וּ לָכֶם֙ מְלֹ֣א חָפְנֵיכֶ֔ם פִּ֖יחַ כִּבְשָׁ֑ן וּזְרָק֥וֹ מֹשֶׁ֛ה הַשָּׁמַ֖יְמָה לְעֵינֵ֥י פַרְעֹֽה׃
И сказал Господь Моисею и Аарону: 'Возьми себе горсти сажи печи, и пусть Моисей бросит ее в небо в глазах фараона.
Rashi
וזרקו AND [THE PRIESTS] … SHALL DASH [THE BLOOD ROUND ABOUT] — He (the priest) stands below and dashes the blood from the vessel upon the altar wall below the red line over against the two diagonally opposite corners (the north — east and the south — west corners so that there is blood on the four sides). That is what Scripture means when it says, סביב, “round about” — that the blood shall be put upon all the four sides of the altar. Or I might think that it means he (the priest) shall place it (the blood) right round the altar as a line! Scripture, however, states, וזרקו, “and they shall dash [the blood]” (i. e. fling it; cf. Exodus 9:8; thus implying that he must be standing some distance away), and it is impossible to put it right round the altar by flinging it against it. — The explanation given above as to how it was actually done is arrived at by the following argument: If we go only by the meaning of the word וזרקו alone, one might have thought that it would suffice with one “flinging” only (that we need merely fling the blood against one side of the altar)! Scripture, however, adds סביב, “round about”! How then can this be done? He makes two flingings but in such a manner that they virtually constitute four, as stated above). (Sifra, Vayikra Dibbura d'Nedavah, Section 4 9)
Rashi
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.
Siftei Chakhamim
The meaning of sprinkling. The word זרק is an expression meaning the same as as in, “And I will sprinkle ( וזרקתי ) purifying water upon you” (Yechezkel 36:25). But it does have the meaning as in, “And let Moshe cast ( ויזרוק ) it heavenward” (Shemos 9:8), which means actual throwing.