AABB
The rhyme scheme depends on the last word of each line, and in the case of this couplet the last words are "we", "thee", "man" and "can". Since the first word is given the letter A (along with any subsequent line that rhymes with the first line), lines 1 and 2 get an A. "Man" changes the rhyme so it gets a B, and so does line 4 because "can" rhymes with "man".
