Paul next begins a discussion about how love will stand the test of time. He states that very plainly when he says love never fails. Everything else will but not love. Prophecy will, words will and knowledge will. Because we will never know everything there is to know as long as we are on this earth.
All prophecy is limited.
All knowledge is fleeting. Think of this - man used to think the earth was flat. You see as we grow up our understanding grows up with us. As knowledge increases we find more and more to know. As we grow our language changes our understanding changes.