Answer: The two parts are 1) "Love is not love / Which alters when it alteration finds" and 2) "Or bends with the remover to remove."
Explanation: Just to elaborate a little on the answer, it can be added that in this famous sonnet William Shakespeare described love, by contending what it is and what it is not. In these lines the writer is saying that love is not love when it changes because the beloved one has changed and it does not disappear when he or she has departed. By repeating the same words or words with the same root - love, love, alters, alteration, remover, remove - Shakespeare was able to emphasize his message and to create a more effective emotional response on the reader.