The question of whether Judas Iscariot took part in the institution of the Lord's Supper before leaving the Passover meal is debated among exegetes. The Gospel accounts do not allow an absolutely certain answer, since each emphasizes different aspects of that decisive evening.
The Gospel of John is the only one to report Judas's departure in detail. After handing him the dipped morsel, Jesus implicitly announces the identity of the betrayer. John then states: “Judas, having received the morsel, went out immediately. And it was night” (John 13.26-30). The evangelist immediately adds: “When he had gone out, Jesus said, Now is the Son of Man glorified” (John 13.31). This transition marks an important narrative break: from that moment, Jesus speaks exclusively to the eleven disciples who remained with him.
The Synoptic Gospels, for their part, report the institution of the bread and the cup (Matthew 26.26-29; Mark 14.22-25; Luke 22.19-20), but they do not state explicitly when Judas leaves the room. Their main aim is not to provide a detailed chronology of all the events but to bring out their theological significance.
Two main interpretations are therefore proposed. According to the first, widely held by many commentators, John follows the chronological order of events here. Judas would have left immediately after receiving the dipped morsel, before Jesus instituted the Lord's Supper. In this view, he would not have shared in the bread and the cup symbolizing the new covenant.
According to a second interpretation, the Synoptic accounts reflect the historical order of the evening more faithfully. Judas would then still have been present at the institution of the Lord's Supper and would have shared the bread and the cup with the other disciples before leaving the meal.
In the absence of an explicit statement in Scripture, it is impossible to settle the matter with absolute certainty. Nevertheless, the progression of John's account, which stresses Judas's immediate departure before the long discourse addressed to the eleven disciples (John 13.31-17.26), leads many exegetes to consider it more probable that Judas did not take part in the Lord's Supper proper. This conclusion nevertheless remains an exegetical deduction and not an explicit statement of the biblical text.