Hello. You did not say which poem this question refers to, which makes it impossible for it to be answered accurately. However, I will try to help you in the best possible way.
In general, we can say that the first lines of a poem have the effect of determining the tone and the main subject which the poem will develop in the following lines. In this way, the first two lines can fulfill this role, mainly in relation to the tone of the poem.
Exertion maybe?
I think it might be exertion because it seems to fit... tell me if I'm wrong.
