Talmud for Bekhorot 4:6
הַנּוֹטֵל שְׂכָרוֹ לָדוּן, דִּינָיו בְּטֵלִים. לְהָעִיד, עֵדוּתָיו בְּטֵלִין. לְהַזּוֹת וּלְקַדֵּשׁ, מֵימָיו מֵי מְעָרָה וְאֶפְרוֹ אֵפֶר מִקְלֶה. אִם הָיָה כֹהֵן וְטִמְּאָהוּ מִתְּרוּמָתוֹ, מַאֲכִילוֹ וּמַשְׁקוֹ וְסָכוֹ. וְאִם הָיָה זָקֵן, מַרְכִּיבוֹ עַל הַחֲמוֹר. וְנוֹתֵן לוֹ שְׂכָרוֹ כַּפּוֹעֵל:
If one takes a fee to judge, one's rulings are invalid. [If one takes a fee] to testify, one's testimony is invalid. [If one takes a fee] to sprinkle [ashes of the red heifer] or to mix [them with water], the water is like cave water and the ashes are the ashes of a regular fire. If a priest was made impure to eat <i>Terumah</i> [by the one who took the fee], one must feed him, give him drink and anoint him. If the person was old, one must transport him on a donkey give him his wages like a worker [idled from his work].