Why does the Torah repeat the prohibition against drinking blood here?
Rashi: Because we might otherwise have thought that, since the animal may be eaten without having to redeem it, despite the fact that it came from an Isur (since it was holy), the blood is also included in the Heter.
Ha'amek Davar #1 (citing Bechoros 16a): The Torah mentions it in order to forbid the Cheilev of Pesulei ha'Mukdashin. 1
Ha'amek Davar #2: Because we might otherwise have thought that blood of Beheimos is forbidden only if they are eligible to be brought as Korbanos.
Bearing in mind that the Cheilev of a deer and gazelle is permitted. And we learn it 'Im Eino Inyan'
Why is the word "Rak" coming to preclude?
Rashi: Refer to 15:23:1:1
Midrash Tana'im #1: It precludes someone who transgressed without warning from Malkos.
Midrash Tana'im #2: It precludes from Malkos someone who ate less than a k'Zayis.
Pesulei ha'Mukdashim are considered Kil'ayim, since they have Dinim of both Kodshim and Chulin (Makos 22a). If not for the current Pasuk, we would have thought that one is liable for the blood both due to Dam Kodshim and due to Dam Chulin (It is not clearr however, what this has to do with blood - since it is equally applicable to the Basar of Pesulei ha'Mukdashin? and the same Kashya pertains to answers #3 & #4.
What is the significance of the comparison of blood to water?
Refer to 12:16:2:1-3.
