{16} Jesus answered them, Have not I chosen you twelve, and one of you is a devil?

(16) The number of the professors of Christ is very small, and among them also there are some hypocrites, and those worse than all others.

People's New Testament

6:70 One of you is a devil. A demon, in the original; diabolical, or under the influence of the evil one. Notice in this remarkable discourse the progressive thought: (1) The Lord announces the Bread of God that giveth life to the world (Joh 6:33). (2) He declares that he is the Bread of Life (Joh 6:48,50). (3) The Bread of life must be eaten by partaking of his flesh and blood (Joh 6:51-56). (4) This is done spiritually, by the spirit feeding upon his life and words (Joh 6:63).

Wesley's Notes

6:70 Jesus answered the - And yet even ye have not all acted suitable to this knowledge. Have I not chosen or elected you twelve? - But they might fall even from that election. Yet one of you - On this gracious warning, Judas ought to have repented; is a devil - Is now influenced by one.

Scofield Reference Notes

Margin devil

Gr. "diabolos," adversary, usually trans. Satan. Cf. See Scofield Note: "Rev 20:10". Also see, Jn 13:27.

Jamieson-Fausset-Brown Bible Commentary

70. Have not I chosen . and one of you is a devil:-"Well said, Simon-Barjonas, but that 'we' embraces not so wide a circle as in the simplicity of thine heart thou thinkest; for though I have chosen you but twelve, one even of these is a 'devil'" (the temple, the tool of that wicked one).

Matthew Henry's Concise Commentary

6:66-71 When we admit into our minds hard thoughts of the words and works of Jesus, we enter into temptation, which, if the Lord in mercy prevent not, will end in drawing back. The corrupt and wicked heart of man often makes that an occasion for offence, which is matter of the greatest comfort. Our Lord had, in the foregoing discourse, promised eternal life to his followers; the disciples fastened on that plain saying, and resolved to cleave to him, when others fastened on hard sayings, and forsook him. Christ's doctrine is the word of eternal life, therefore we must live and die by it. If we forsake Christ, we forsake our own mercies. They believed that this Jesus was the Messiah promised to their fathers, the Son of the living God. When we are tempted to backslide or turn away, it is good to remember first principles, and to keep to them. And let us ever remember our Lord's searching question; Shall we go away and forsake our Redeemer? To whom can we go? He alone can give salvation by the forgiveness of sins. And this alone brings confidence, comfort, and joy, and bids fear and despondency flee away. It gains the only solid happiness in this world, and opens a way to the happiness of the next.