Richard, I appreciated your post, and as I reflect upon John 6:70, it becomes clear that Christ was aware of the unconverted state of Judas, and that Judas was possessed of a devil. We actually read about this earlier in The Desire of Ages, and Jesus already knew that this man was tampering with sin to the extend that Satan was holding him under his power:
Before the Passover Judas had met a second time with the priests and scribes, and had closed the contract to deliver Jesus into their hands. Yet he afterward mingled with the disciples as though innocent of any wrong, and interested in the work of preparing for the feast. The disciples knew nothing of the purpose of Judas. Jesus alone could read his secret. Yet He did not expose him. Jesus hungered for his soul. He felt for him such a burden as for Jerusalem when He wept over the doomed city. His heart was crying, How can I give thee up? The constraining power of that love was felt by Judas. When the Saviour's hands were bathing those soiled feet, and wiping them with the towel, the heart of Judas thrilled through and through with the impulse then and there to confess his sin. But he would not humble himself. He hardened his heart against repentance; and the old impulses, for the moment put aside, again controlled him. Judas was now offended at Christ's act in washing the feet of His disciples. If Jesus could so humble Himself, he thought, He could not be Israel's king. All hope of worldly honor in a temporal kingdom was destroyed. Judas was satisfied that there was nothing to be gained by following Christ. After seeing Him degrade Himself, as he thought, he was confirmed in his purpose to disown Him, and confess himself deceived. He was possessed by a demon, and he resolved to complete the work he had agreed to do in betraying his Lord. {DA 645.1}
We do not know at what point exactly Judas became "possessed by a demon," but it is clear that at the time of the foot washing performed by Christ, Satan had such hold of Judas that Judas chose to continue in the way of perdition. Jesus had done all that could be done to save this poor, wretched man who thought himself wiser than Christ. After Judas left the passover supper, we read that his probation closed (while he was still alive!):
As they realized the import of His words, and remembered how true His sayings were, fear and self-distrust seized them. They began to search their own hearts to see if one thought against their Master were harbored there. With the most painful emotion, one after another inquired, “Lord, is it I?” But Judas sat silent. John in deep distress at last inquired, “Lord, who is it?” And Jesus answered, “He that dippeth his hand with Me in the dish, the same shall betray Me. The Son of man goeth as it is written of Him: but woe unto that man by whom the Son of man is betrayed! it had been good for that man if he had not been born.” The disciples had searched one another's faces closely as they asked, “Lord, is it I?” And now the silence of Judas drew all eyes to him. Amid the confusion of questions and expressions of astonishment, Judas had not heard the words of Jesus in answer to John's question. But now, to escape the scrutiny of the disciples, he asked as they had done, “Master, is it I?” Jesus solemnly replied, “Thou hast said.” {DA 654.2}
In surprise and confusion at the exposure of his purpose, Judas rose hastily to leave the room. “Then said Jesus unto him, That thou doest, do quickly.... He then having received the sop went immediately out: and it was night.” Night it was to the traitor as he turned away from Christ into the outer darkness. {DA 654.3}
Until this step was taken, Judas had not passed beyond the possibility of repentance. But when he left the presence of his Lord and his fellow disciples, the final decision had been made. He had passed the boundary line. {DA 654.4}
Another way to say that "He had passed the boundary line" is "He closed his probation in rejecting his Lord's final plea to repent." When we read of Judas in today's chapter, we see Jesus interact with a man who is unrepentant, but who sorrowed over the effects of his sin:
Judas now cast himself at the feet of Jesus, acknowledging Him to be the Son of God, and entreating Him to deliver Himself. The Saviour did not reproach His betrayer. He knew that Judas did not repent; his confession was forced from his guilty soul by an awful sense of condemnation and a looking for of judgment, but he felt no deep, heartbreaking grief that he had betrayed the spotless Son of God, and denied the Holy One of Israel. Yet Jesus spoke no word of condemnation. He looked pityingly upon Judas, and said, For this hour came I into the world.
Such a sad record of how dangerous it is to tamper with sin and sacred trusts! Let us take heed to the warning!
But what also stands out to me in this chapter is how Christ dealt with this wicked, base man who would stoop to do such a thing. As Judas "repented himself" (Matthew 27:3) it was not true repentance that is the gift of God received into the soul that changes the heart (see how Acts 5:31 speaks of how through Christ, God is able to "give repentance"). Judas' "repentance" was but a response of self, from a man who was lost and whose probation had closed. What more could God do for Judas? Jesus did all He could to save this man, but Judas chose to walk in darkness, to live for self and to cherish the way of the flesh rather than to value the things of the spiritual kingdom. Satan had control of him, because Judas refused the help offered him in Christ.
As I see Jesus' dealings with Judas, I am encouraged to know that this is also how we are to deal with the grievously erring, for we are to do all that is possible to give them opportunity to repent. But like Judas, each will close his or her own probation by coming to the point when they will not turn and any additional light will not be received. Because we do not know when that point is reached as we deal with souls (for we cannot read hearts), let us be kind, patient, and forbearing (by beholding Jesus' loveliness and abiding in Him through His Spirit).
We need Jesus continually to be able to deal graciously with souls who are unconverted, and yet who make a high profession of religion as did Judas. We have no wisdom of ourselves, and it is as we abide in Christ that divine grace is given us in our dealing with souls. Praise the Lord!