Mishnayos Yadayim Perek 2 Mishnah 3

חזרו ליד טהורה - for since the first [rinsing of the hands] did not go past the wrist, the second [rinsing of the hands] were not defiled through their going out beyond the rest But when the first [rinsing of the hands] and the second [rinsing of the hands] went out beyond the wrist and returned to the hand, it is defiled, because the second [rinsing of the hands] with the first that went beyond the wrist, for the second [rinsing of the hands] does not purify the first [that go forth] beyond the wrist, but rather only until the wrist alone they purify.

נטל את הראשונים לידו אחת – that he poured the first [rinsing of the hands] on each individual hand separately, and afterwards combined the two hands to pour upon them the second [rinsing of the hands], his hands are impure. For when he combined his hands, his hands wee defiled through their contact/touching one another, for eh water that was on this one defiles the water that was on top of its fellow [hand], like that they defiled a loaf of heave-offerings, and the hands were defiled on account of the impure liquids. But when he poured the second [rinsing of the hands], they did not purify the first [rinsing of the hands], because they were defiled on account of the waters of its partner, but on the contrary also the second [rinsing of the hands] were defiled by them. And especially when he poured the first [rinsing of the hands] this one (i.e., one hand) for itself and that one (i.e., the other hand) for itself, but if he poured the first [rinsing of the hands] for the two hands as one, the two hands are considered as one hand and hey don’t defile one another. Such is what I found as an explanation of this Mishnah in the explanations/commentaries of my Rabbis/Teachers. But Maimonides explained, that if he poured the first [rinsing of the hands] on only one hand alone, and afterwards combined both hands to pour upon them the second [rinsing of the hands], his hands are impure, for the second [rinsing of the hands] are defiled by the hand that was not purified, and they return and defile the pure hand.

ושפשפה בחברתה (and rubbed his other hand) – that he had not poured [water upon to ritually cleanse], the water that was on it was defiled on account of the other hand that had not been poured upon, and they return and defile the hand that he poured [water upon].

בראשו או בכותל – if he rubbed it on his head or on a wall in order to dry it.

טהורה – but if after he rubbed it he returned and touched the same water that had come from his hand to his head or to the wall, it is defiled.. For those waters are defiled and they return and defile the hand that touched them. Even though that all the while that he did not rub, they are [purified/ as we need to say] with the rubbing, for when he rubbed and went back and touched, he made it worse.

נוטלים ארבעה וחמשה זה בצד זה – and we don’t worry because of four things, because lest they were defiled that they (i.e., the water) fell from one hand to the other, or lest they have the law of water that work had been done with them, or because lest they didn’t pour from a vessel, or because perhaps they didn’t pour from one-quarter of a LOG.

ובלבד שירפו (that they lie loosely) – that their hands [would lie loosely] so that there wouldn’t be an interposition/an intervening object there.