But I laugh,And eat well,And grow strong. (lines 5-7)
Here, the speaker is making the best of a very bad situation. It would be easy to feel angry and depressed in the face of enslavement and/or oppression. But instead, the speaker in this poem laughs. Yes, he laughs. Why? Because he firmly believes that if he eats well and grows strong (a metaphor for coming together in solidarity as a race), he'll overcome the chains (both literal and metaphorical) that bind him. Now that's some serious ambition.
Tomorrow,I'll be at the table (lines 8-9)
A big part of being ambitious is keeping your eye on the prize: the kind of future you want. In this section, the speaker envisions a "tomorrow" in which he'll be recognized as equal to whites. He doesn't literally mean tomorrow, as in the very next day – he's talking about a slightly more distant future, maybe even a future that he won't personally get to see. But it's not himself he's worried about, really – it's all of his "darker brothers."
Nobody'll dareSay to me,"Eat in the kitchen,"Then. (lines 11-14)
Ambition is also all about confidence – the ability to stand up for yourself and to command respect from other people. Here, the poem references a future in which the main character – and, by proxy, his whole race – will be treated as equal. Considering the historical situation of the poem, that's a pretty big dream. One might say a particularly ambitious dream.