Then again called they the man that was blind. — He had not been present during the interview with his parents. They now wish him to believe that they have ascertained from his parents either that he was not their son, or that he was not really born blind. It is useless for him, therefore, to persist in his belief that a prophet had given him the power to see.
Give God the praise. — Better, Give glory to God. This phrase is very generally misunderstood, though almost all competent authorities are agreed as to its true meaning. It is not “Give God the praise for your cure, instead of this Man, who is a sinner. Trace the gift to its true source, and give glory to the true Giver.” This is wholly opposed to the context, for they are assuming that no cure has really taken place. The phrase is rather an adjuration calling upon the man to speak, as in God’s presence, and confess the whole truth. (Comp. the words of Joshua to Achan, “My son, give, I pray thee, glory to the Lord God of Israel, and make confession unto Him; and tell me now what thou hast done; hide it not from me,” Joshua 7:19. Comp. also 1 Samuel 6:5; Jeremiah 13:16; 1EEsther 9:8; Revelation 16:9.)
We know that this man is a sinner. — Some of them had said before that He was not from God, while others had felt that such miracles were inconsistent with the belief that He was a sinner. The man himself had declared his simple conviction that He was a prophet (John 9:16-17). They now assert, with the emphasis of an authority which is beyond question, that they know Him to be a sinner.