Lines 1 and 2 and lines 5 and 6 because if you give something positive to the world such as laughter in line 1 and singing in line 2, you will receive a positive response from the world (society), for example the world will "laugh with you" and the "hills will answer", but the opposite is true for if you give something negative into the world such as weeping in line 2 and sighing in line 6, you will receive a negative response