Yoma 60 - The order of the Yom Kippur service

The High Priest who performs all Yom Kippur services should do each step in order, as prescribed in the Torah. If, for example, he changes the steps in the previously described service of the ox's and goat's blood, sprinkles the goat's blood first, and then the ox's - he must repeat the sprinkling of the goat's blood again. Another kind of mess-up: if he accidentally spills the blood, he must slaughter another animal, receive blood in a vessel, bring it back, and restart the sprinklings. 

Rabbi Elazar and Rabbi Shimon disagree on the last point and say that he restarts from the last successful sprinkling. For example, if he did three sprinklings and then the blood spilled, he goes to the Courtyard, slaughters another animal, receives its blood, but now restarts from the sprinkling number four.

Rabbi Yehudah qualifies the first rule of "everything in order" - it only applies to the steps in the Holy of Holies, but not in the Holy. And Rabbi Nechemiah adds another qualification: the rule applies only to the steps done in white vestments but not in the regular golden vestments.

Art: Study of a Goat by Pieter Boel