Shemot 12:22-23

Orthodox Jewish Bible

²² And ye shall take a bunch of hyssop, and dip it in the dahm that is in the basin, and strike the mashkof (lintel) and the two mezuzot (door sideposts) with the dahm that is in the basin; and none of you shall go out the door of his bais until boker.

²³ For Hashem will pass through to strike the Mitzrayim; and when He seeth the dahm upon the mashkof, and on the two mezuzot, Hashem will pasach (pass over, spare, skip) the entrance, and will not permit the Mashkhit (Destroyer, i.e., Hashem’s emissary of judgment, [see Num 22:31 on the Malach Hashem]) to enter unto your batim to strike.