But I know him. — In contrast with their ignorance is His own full knowledge, which belonged to One only. (See Note on John 1:18.) The pronoun “I” here, as “ye” immediately before, is emphatic.
For I am from him, and he hath sent me. — This knowledge is here based upon His oneness of essence, and upon His true mission. He knows God because He is from Him, and in union ever one with Him. He knows God because He is in His human nature the representative of the Divine to mankind.