Thou knowest all things — Even our hearts. Although no question is asked thee, yet thou answerest the thoughts of every one. By this we believe that thou camest forth from God — They, as it were, echo back the words which he had spoken in John 16:27, implying, We believe in God; we believe also in thee.
Related Commentaries of John 16:30
John 16:30
30 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.