Let's take a look at these two sentences: "I like him" (Ich mag ihn), and "I help him" (Ich helfe ihm). In English, we use "him" in both sentences, whereas in German we need to use the Akkusative after the verb "to like" (mögen) and the Dative after the verb "to help" (helfen), which is why we have to differentiate between "ihn" and "ihm". But more on this in following chapter!