From the TheologyOnline debate Does God Know Your Entire Future. Bob Enyart writes:
Settled Interpretation: By elevating the quantitative attributes of omniscience, control, omnipotence, and immutability, above God’s qualitative attributes of being relational, good, and loving, Calvinists believe that God is glorified more by Judas carrying out his treachery, than if he had repented and being broken, sought forgiveness.
Open Interpretation: Because the quantitative attributes should not take precedent over God’s being relational and loving, which are among His highest attributes, therefore no creaturely action can glorify God more than to obey the greatest command, which is to love Him. Thus if Judas had repented, Jesus would not be angered, but overjoyed, as the Shepherd who left the ninety-nine to recover the one lost sheep. God would care nothing of Judas failing to live up to the expected betrayal, as compared to the glory of reconciliation.
So let me restate your question into its historical narrative. Earlier, Judas had left the upper room after finding out that Jesus already knew about his betrayal. In the evening after dinner the Lord took the eleven for a walk over the Brook Kidron and up the side of the Mount of Olives to Gethsemane. And in that garden, the Lord spoke the most mournful prayers ever uttered, about the dear cost of our salvation. And now watch what Calvinists think is their greatest nightmare, and see what Openness possibilities would look like actually playing out in human history. As Jesus is praying, the traitor appears, but not with a cohort of temple guards. He comes alone. And he stumbles, and falls at the feet of his Lord. “Master…, I…, I…,” but he can’t stop crying. “Master…, Master…,” his words not able to break through his sobs. Peter stirs, and awoken by the wailing, comes to see what is happening. He has a weapon, but does not need to draw his sword. For no guards were there. And Malchus was still back at the high priest’s courtyard, warming himself at a fire of coals. Peter sees his fellow disciple, Judas, prostrate and consumed in tears. He was pleading with the Lord, for something Simon couldn’t understand. Judas was overcome with grief, and the sound of wailing brings James and John, who see Jesus put his arms around Judas’ head. And the Lord cleans his nose and eyes with the edge of His robe. Then the Lord asked him, “Who are you seeking?” And Judas couldn’t answer. And so He kissed him, and said, “I know, Judas, I know.”
“I forgive you.”
Sam. Consider the entirety of who Judas was and ever will be. What could he ever have done that could have glorified God more than to repent in Gethsemane? If Judas had repented, as did Nineveh after God promised destruction in forty days, God would not cease to be God. Rather, He and the angels in heaven would rejoice. The Evangelists would not feel defeated, but they would glory recording such an event in their Gospels, as does the Scripture when Nineveh repented and avoided God’s prophesied destruction forty days later. Jonah lamented that God’s mercy superseded His prophecy (though it did!). And Settled View proponents seem to suggest they would do likewise. Calvinists always bring up Judas, suggesting that God could not be God if Judas had repented, but He survived Nineveh. Actually, God wanted to be wrong about Nineveh, because love influences Him. And God could have survived Judas also. If Judas had repented, Christ might have given Matthias a different task, of engraving this story into the walls of the New Jerusalem [Rev. 21:14] just beneath the name of Judas Iscariot. Calvinists do not lament the fact that Nineveh repented (true?). And it would be EXACTLY the same situation if Judas had repented.