Mishnah Parah 7:5: One who [wants to] fill [water] for himself and for a chatat [the red heifer sanctification ritual], he [should] fill for himself first and tie it to the [carrying] pole, and afterwards fill for the chatat. And if he filled for the chatat first and afterwards he filled for himself, it is invalid. He places his own behind him [on the pole holding the water vessels], and the one for the chatat in front of him. And if he placed the one for the chatat behind him, it is invalid. If they were both for chatat, he places one in front and one behind and they are valid since it is impossible [to do otherwise].

הַמְמַלֵּא לוֹ וּלְחַטָּאת, מְמַלֵּא אֶת שֶׁלּוֹ תְּחִלָּה וְקוֹשְׁרוֹ בָאֵסֶל וְאַחַר כָּךְ מְמַלֵּא אֶת שֶׁל חַטָּאת. וְאִם מִלֵּא שֶׁל חַטָּאת תְּחִלָּה וְאַחַר כָּךְ מִלֵּא אֶת שֶׁלּוֹ, פָּסוּל. נוֹתֵן אֶת שֶׁלּוֹ לַאֲחוֹרָיו וְאֶת שֶׁל חַטָּאת לְפָנָיו. וְאִם נָתַן אֶת שֶׁל חַטָּאת לַאֲחוֹרָיו, פָּסוּל. הָיוּ שְׁנֵיהֶן שֶׁל חַטָּאת, נוֹתֵן אֶחָד לְפָנָיו וְאֶחָד לַאֲחוֹרָיו, וְכָשֵׁר, מִפְּנֵי שֶׁאִי אֶפְשָׁר:

Mishnah Parah 7:6: One who takes a rope [borrowed for drawing water for the chatat ritual] in his hand [and goes to return it to its owner, after drawing water with it], if it is on his way, it [the water for the ritual] is valid. And if [he goes] out of his way [to return the rope to it owner], it is invalid [since carrying the rope unnecessarily is considered unrelated work, which invalidates the waters]. Regarding this, someone went to [the sages of] Yavneh on three festivals [to ask about this ruling], and on the third festival, they validated [the waters] as a temporary teaching [i.e. one which was only applied because of pressing circumstances].

הַמּוֹלִיךְ אֶת הַחֶבֶל בְּיָדוֹ לְדַרְכּוֹ, כָּשֵׁר. וְשֶׁלֹּא לְדַרְכּוֹ, פָּסוּל. זֶה הָלַךְ לְיַבְנֶה שְׁלשָׁה מוֹעֲדוֹת, וּבְמוֹעֵד שְׁלִישִׁי הִכְשִׁירוּ לוֹ הוֹרָאַת שָׁעָה: