What is the meaning of "[Lema'an] Timchatz Raglecha b'Dam"?
Rashi #1: When we will cleave the enemy's head, our feet will sink in their blood. Timchatz is an expression of cleaving in blood, like "u'Machatzah v'Chalfah Rakaso" (Shoftim 5:26), like a valley. A Mishnah (Shekalim 8:1) says 'Olei Regalim were Bok'im until their knees in blood.'
Rashi #2: Timchatz is a Kli used to draw wine from a pit (Avodah Zarah 72b).
Radak #1: This is like Techmatz (the letters are reversed), reddening - "Chamutz Begadim" (Yeshayah 63:1). The verse means, in order that your foot will redden; also refer to 68:24:2:2. "Raglecha" refers to Yisrael (your feet).
Radak #2: "Raglecha" refers to Hashem. It is a metaphor, like "Chamutz Begadim mi'Batzrah" (Yeshayah 63:1). "B'Dam" is Samuch to me'Oyvim 1 , even though words interrupt in between. There are many verses like this, e.g. "va'Yar Ishah Rochetzes me'Al ha'Gag" (Shmuel II, 11:2); it is like va'Yar me'Al ha'Gag Ishah Rochetzes.
Malbim: [The enemies] who return from the land, you (death) will kill them with your sword and your foot will be dirtied from their blood.
Radak: (Normally, when Dam is Samuch, there is a Patach under the Dalet.) Here it is a Kamatz, for the prefix Mem in me'Oyvim causes that it is not an absolute Semichus; it is as if it says b'Dam ha'Nishpach me'Oyvim.
What does the verse teach about your dogs' tongues?
Rashi: Refer to 68:24:3:1.
Radak: [Your foot will redden, and also] the tongue of your dogs that will lick the enemies' blood. They will eat the dead bodies. Kelavecha refers to Yisrael (your dogs).
Malbim: Also your dogs' tongues will be dirtied from their blood. The verse depicts death as an execution officer who has dogs that go with him to eat those whom he kills.
What is the meaning of "me'Oyvim Minehu"?
Rashi: [The dogs' sustenance] will be from the enemies' blood. We find that this is an expression of food - "Asher Minah Es Ma'achalchem
