Ramban #1: In Mishpatim it is an Asei. Here the Torah is adding a Lo Sa'Asei. ¹

Ramban #2: Here the Torah is adding that one is obligated to help load the animal if the animal together with the load have fallen on to the ground. ²

Ramban #3: In Mishpatim the Torah is discussing a donkey, which it is common to load heavily and it staggers under the load; here it extends the obligation with regard to an ox - to teach us that one is obligated to help load it even though the owner should not have loaded it so heavily.

Ramban #4: In Mishpatim, the Torah wrote "Oyvecha" and "Sona'acha", whereas here it writes "Achicha", to teach us to remember the brotherhood and forget the hatred and help him. ³

Mechilta (Parshas Mishpatim): To obligate giving a hand to pick up the animal if it has fallen down.

Sifri: To obligate to load the animal if the owner fails to help load because he is old or sick. ⁴

According to the Sugya in Bava Metzi'a, 31a "Azov Ta'azov" is referring to unloading and "Hakem Takim", to loading.

Refer to 22:4:1:3.

Sifri: "Noflim" - 'to preclude where the animal is standing erect' ¹ "be'Derech" - 'to preclude where the animal is (lost) inside the stable'.

Rashi: It entails assisting a fellow Jew to reload the baggage that fell off his animal's back on to the animal.

Bava Metzi'a, 31a: To teach us that one is obligated to load the animal even if the owner is not there. ¹

Sifri: To teach us that if he loaded it and it fell down again - even four or five times, he is obligated to load it gain. ²

Rashi: To teach us that one is only obligated to help load if the owner himself is also loading, ¹ but not if he sits himself down and says 'Since it's your Mitzvah, if you want to fulfill it, go ahead!' ²