John 16:28-31

I came forth from the Father, and am come into the world: again, I leave the world, and go to the Father. His disciples said unto him, Lo, now speakest thou plainly, and speakest no proverb. Now are we sure that thou knowest all things, and needest not that any man should ask thee: by this we believe that thou camest forth from God. Jesus answered them, Do ye now believe?