The Torah forbids "shatnez" ("intertying" wool and linen together). However, unlike other forms of "kil'ayim" (combinations of various phenomena like planting different types of seed or ploughing with different animals), there is an exception to the rule: "shatnez" was not only allowed but required in the priestly garments, which combined dyed-wool and linen threads. According to the rabbis, this exemption to "shatnez" applied only while performing priestly service. Rabbinic Judaism (but not Karaite Judaism or Samaritanism) makes a further exemption to this law for "tzitzit", based on the Torah's juxtaposition of the laws for "shaatnez" and "tzitzit" in Deuteronomy 22:11-12. Thus, according to rabbinic Judaism, both laymen and priests were supposed to wear mixtures of wool and linen all the time. From this perspective, the "shatnez" of the layman reflects that of the priest.