Answer:
The thought that is implied by the poem's first four lines is: the speaker wishes to live a carefree life.
Step-by-step explanation:
Let's first take a look at the lines we are analyzing here:
To fling my arms wide
In some place of the sun
To whirl and to dance
Till the white day is done.
There is no way to know if the speaker is male or female, young or old. It could be Hughes himself, but it could also be a child. The description is quite childlike: "to fling my arms wide" is something children are more likely to do. But, imagine an adult, oppressed, hardened by prejudice and struggle, who finally achieves his dreams. To finally be free of worried, of fear, and of injustice. Wouldn't that adult feel like a child again? Carefree and happy?
That is what the four lines above seem to emphasize. The speaker wants a carefree life. He or she wants to play, to dance, to laugh his days away.