Commentaire sur Parah 11:4

כל הטעון ביאת מים מדברי תורה – as for example, a person who comes in contact with all primary sources of ritual uncleanness (see the first chapter of Tractate Kelim)

All that require immersion in water according to the rulings of the Torah defile consecrated things, terumah, unconsecrated food, and [second] tithe; And he is forbidden to enter the sanctuary. A person who has been defiled by a "father of impurity" requires immersion in a mikveh. See for instance Leviticus 11:32 with regard to one who has had contact with a sheretz. Such a person defiles any food with which he has had contact, be it consecrated food (kodesh), terumah, unconsecrated food (hullin) or second tithe. He is also forbidden from entering the sanctuary (the Temple.)

מטמא את הקודש ואת התרומה – because it is first-degree of ritual uncleanness, it makes it second-degree of ritual uncleanness and with tithes, and third-degree of ritual uncleanness with heave-offerings and fourth degree of ritual uncleanness with Holy Things.

After immersion [but before the sun sets] he defiles holy things and invalidates terumah, the words of Rabbi Meir. But the sages ruled: he invalidates consecrated things and terumah. But he is permitted to unconsecrated food and [second] tithe. And if he entered the sanctuary, whether before or after his immersion, he incurs guilt. According to Rabbi Meir, after he has immersed in the mikveh, the person has the status of "second degree defilement." He causes terumah to have third decree impurity, which causes it to be invalid but not impure. And he causes holy things to have fourth degree impurity. The other sages say that since he has immersed in the mikveh he does not defile even holy things. He merely invalidates both holy things and terumah. After having immersed in the mikveh, he causes no defilement or invalidation to common food or to second tithe. However, when it comes to entering the sanctuary, he is prohibited even after going to the mikveh. He can't enter the sanctuary until he has immersed in the mikveh and the sun has set.

לאחר ביאתו – that he ritually immersed and did not have a sunset pass, he has the law of second degree of ritual uncleanness, and makes heave-offering third-degree of ritual uncleanness and Holy Things fourth-degree of ritual uncleanness.

וחכמים אומרים פוסל בקודש – in the same way that a person who immersed himself that day invalidates heave-offering, so he invalidates Holy Things, but he does not defile Holy Things, for since he immersed his defilement is weakened, and he is made equivalent to something invalid, [but] he is not made equivalent to being impure.

ואם בא אל המקדש – all who are required to ritually immerse from the [Written] Torah, who comes to the Sanctuary, that is to the Israelite Courtyard, even after he had immersed prior to his sunset, is liable [for extirpation]. And even to the Women’s Courtyard, a person who immersed himself that day is forbidden to enter, but he is not liable [for extirpation] other than in the Israelite courtyard.