Ibn Ezra on Leviticus 15:17

היה נראה לנו שצריך רחיצ׳‎ הבגד או העור אם היה בו זרע לח או יבש והאמת כדברי הקבלה: It would appear to us³⁴From the plain meaning of the text. that the garment or the skin requires washing if it has wet semen or dry semen on it.³⁵If it come into contact with wet or dry semen, for the verse does not differentiate among them. However, the truth lies with the words of tradition.³⁶The Mishnah in Niddah 7:1 states, “Semen [coveys] uncleanliness when wet but not when dry.”