SPRINKLING (Heb. zāraq, nāzâh, Gr. rhantizein). Sprinkling of blood, water, and oil formed a very important part of the act of sacrifice. In the account of the forming of the covenant between the Lord and Israel (Exod.24.6-Exod.24.8), half of the blood was sprinkled on the altar and the rest on the people. When Aaron and his sons were consecrated, some blood was sprinkled on the altar and some on Aaron and his sons and on their garments. In the various offerings—burnt, peace, sin—blood was always sprinkled. Sprinkling was sometimes done in handfuls, sometimes with the finger, and sometimes with a sprinkler—a bunch of hyssop fastened to a cedar rod.
International Standard Bible Encyclopedia (1915)
sprin’-k’-l, sprin’-kling (zaraq, nazah; rhantizein): The first word means "to toss" or "scatter abundantly," e.g. in handfuls, as dust on the head (Job 2:12) or blood from a bowl (Ex 9:8). The other Hebrew word is used of sprinkling with the finger (Le 14:7; 16:14, etc.). In the account of Jezebel’s death the word is used in its literal meaning of "spurt" (2Ki 9:33).
In the case of persons who had contracted uncleanness through contact with a corpse, sprinkling with the "water of separation" was part of the process of cleansing. The water of separation consisted of the ashes of a red heifer (slain for the purpose) mixed with running water (Nu 19). A sprinkler was used as in the case of the leper (Nu 19:18). The final sprinkling--on the 7th day--was followed by a bath (Nu 19:19). The "tent" in which the corpse lay, together with all the contents, were thoroughly disinfected.
See Red Heifer.
According to Ex (9:8,10) the plague of "boils and blains" was caused through the sprinkling of ashes ("soot" the Revised Version margin) in the air toward heaven, which settled on man and beast and produced the eruption. The narrative gives no clue in reference to the connection between the ashes and the eruption, but the religious character of the act is obvious. By means of it, the assistance of the Deity was invoked. According to primitive thought, there was no necessary connection between the religious act and the consummation devoutly wished for. The purpose of the religious observance was to influence, or bring pressure to bear upon, the Deity so that He might exert Himself on behalf of the worshipper. It is evident that sprinkling as part of the act of worship was believed to be religiously effectual. It was not symbolical nor morally significant. It was a religious act. It is not denied that in some passages sprinkling is symbolical. According to Eze (36:25) the restored community will experience moral and spiritual renewal. There will be a "new heart" and a "new spirit." The sprinkling with clean water is the outward symbol of the inward lustration. In Isa 63:3 the sacrificial allusion is obvious. The conqueror who strides triumphantly from Bozrah is "besprinkled" with the life-blood (or juice) of his victims. In Isa 52:15 "sprinkle" is a doubtful rendering. There is no apparent connection between bodily disfigurement and national purification. the Revised Version margin renders "startle" (literally, "cause to spring"). The exalted dignity of the "martyr" will excite the wonder of kings and peoples.
In 1Pe 1:2, "sprinkling of the blood of Jesus Christ" is used figuratively of its cleansing efficacy (compare Heb 9:13,14; 10:22).