I hope this post is helpful.
The Cup of Jesus
John 18:10-11: Then Simon Peter, having a sword, drew it and struck the high priest’s slave and cut off his right ear. The slave’s name was Malchus. 11 Jesus said to Peter, “Put your sword into its sheath; shall I not drink the cup which the Father has given me?”
Here John fills in details missing from Luke’s account. Luke tells us that one of Jesus’ disciples struck the ear of the high priest’s servant, however, he does not tell us the identity of the disciple or servant involved. John reveals that the disciple was Peter and the servant was Malchus.
Jesus’ reference to the “cup” evokes the prayer the Synoptics relate Jesus had prayed as he prepared to be arrested: “remove this cup from me” (e.g., Mark 10:36). In fact, in Matthew’s account, Jesus prays this prayer three times (Matt 26:39, 42, 44). Of course, Jesus also links drinking the cup to his passion in Mark 10:38-39, in his response to the request of James and John to sit at his right and left in the coming kingdom:
“You do not know what you are asking. Are you able to drink the cup that I drink, or to be baptized with the baptism with which I am baptized?” 39 And they said to him, “We are able.” And Jesus said to them, “The cup that I drink you will drink; and with the baptism with which I am baptized, you will be baptized…”In the Old Testament the image of the cup is used to symbolize suffering (Ps 75:8) and judgment (Isa 51:17, 22; Jer 25:15-29; 49:12; Lam 4:21; Ezek 23:31-34; Hab 2:16). Yet, given the Passover context and the account of Jesus’ words over the “cup” in the Synoptics at the Last Supper, another connection may be found.
Scott Hahn and others have made the case that the backdrop of the “cup” is the Passover seder, which, according to ancient Jewish sources, involved the drinking of four cups (cf. m. Pesahim 10:1). Many have identified the third cup with the cup which Jesus pronounced the words of institution (“This is my blood…”) over. This is supported by a number of observations. First, the third cup was apparently drunk after the main meal. The earliest account of the Last Supper, which is found in 1 Corinthians 11:23ff, tells us that Jesus took the cup “after supper” and pronounced the Eucharistic words over it. Secondly, the third cup was associated with a blessing and was even referred to as the “cup of blessing”. Thirdly, prior to the meal, a blessing would be pronounced. The “blessing” said over the bread by Jesus at the Last Supper may likely allude to this. Finally, after the supper and the drinking of the third cup, the Hallel psalms were sung. This is probably what is alluded to in Mark 14:26: “ And when they had sung a hymn, they went out to the Mount of Olives” (cf. Matt 26:30).
What is nowhere mentioned is the drinking of the fourth cup. Matthew and Mark both make it clear that they sang the hymn, but both also leave the distinct impression that the meal ended at exactly that point. In fact, Jesus seems insistent after the third cup that he will not drink again of the fruit of the vine. While some have suggested that Jesus simply forgot to properly conclude the Passover seder, it would seem obvious from his repeated prayer in the garden concerning the “cup” that he has not forgotten it.It is only once he is about to die on the cross that Jesus utters the words, “I thirst” (John 19:28). After drinking from the sour wine on the hyssop branch, Jesus exclaims, “It is finished” (John 19:30). G. Feeley-Harnik writes, “When [Jesus] finally cries out in agony, ‘My God, my God, why hast thou forsaken me?’… they offer him vinegar…. He drinks the fourth cup and dies the accursed death….”
Jesus’ drinking of the third cup of the Eucharist therefore is intimately connected to his death on the cross. He completes on the cross what he began in the Upper Room. There Jesus made the promise that he would not drink of the fruit of the vine until he drank it in the restored kingdom. Through his death the kingdom comes and he drinks of the final cup as he enters it. Hahn says it better than anyone:
“Ironically, the hour of his crucifixion and death constituted no defeat; it was rather ‘the day and the hour’ of Jesus’ entrance into the glory of his kingdom, whe he’d drink of the vine anew, just as he had said. But it isn’t his will to drink alone; for Jesus calls us as his disciples, to partake not only of the ‘third cup,’ that is, the ‘cup of blessing’ which we share in the Eucharist (1 Cor 10:16), but also of the ‘fourth cup’ by dying for him (Mk 10:38-39). Only then is the paschal mystery truly fulfilled in us.”
This is why Jesus links the drinking of his cup with martyrdom in his response to James and John’s request. Receiving the Eucharist means entering into the mystery of the cross. This is why Jesus tells James and John—who ask to sit at Jesus’ right and left hand in the Kingdom—“are you able to drink the cup which I must drink”. By receiving the cup of the Eucharist, we unite ourselves to Christ. We say, in effect, “Lord I want to die with you. I want to drink from your cup.”
 It would seem that the later conspiracies against David were understood as a punishment for the affair with Bathsheba. See 2 Samuel 12:10-12; 16:20-23.
 Here we cannot discuss all of the details relating to the dating of the Last Supper. Suffice it to say, the Passover forms the context of the Last Supper and the Passion narrative.
 John Nolland, The Gospel of Matthew (NIGTC; Grand Rapids: Eerdmans, 2005), 1077.
 See Scot McKnight, Jesus and His Death (Waco: Baylor University Press, 2005), 256.
 H. L. Strack and P. Billerbeck, Kommentar Neuen Testament aus Talmud und Midrash (Munchen: 1928), IV/2, 628. John Nolland, The Gospel of Matthew (NIGTC; Grand Rapids: Eerdmans, 2005), 1077: “On the basis of the indication in Lk 22:20; 1 Cor. 11:25 that the cup intended came after the meal, the cup is normally identified as the third cup, but occasionally the fourth cup is preferred.” Nolland goes on to explain that the reason one might identify the Eucharistic cup as the fourth cup is due to the fact that no cup comes after the Eucharistic one. We will address this problem below.
 See Norman Theiss, “The Passover Feast of the New Covenant,” in Interpretation 48 (1994): 17-35; Craig Evans, Mark 8:27-16:20 (WBC 34b; Columbia: Thomas Nelson, 2001), 389.
 Also see Jonathan D. Brumberg-Kraus, "Not by bread alone...": The Ritualization of Food and Table Talk in the Passover Seder and in the Last Supper,” in Semeia 86 (1999), 165 n. 1.
 D. Daube, The New Testament and Rabbinic Judaism (Peabody: Hendricksen, 1995), 331: “The implication is that they go out directly after the ‘hymn’ without drinking the fourth cup.”
 That the vinegar was sour wine, see Josef Blinzler, Trial of Jesus: The Jewish and Roman Proceedings against Jesus Christ Described and Assessed from the Oldest Accounts (I. McHugh & F. McHugh, trans.; Westminster: Newman, 1959), 255; Raymond Brown, The Gospel According to John (AB 29A; New York: Doubleday, 1970)), 2: 909.
 See Raymond Brown, The Death of the Messiah: From Gethsemane to the Grave (New York: Doubleday, 1994), 2:1007: “In 18:11 Jesus said that he wanted to drink the cup the Father had given him; when Jesus drinks the offered wine, he has finished this commitment made at the beginning of the P[assion] N[arrative].”
 The Lord’s Table: Eucharist and Passover in Early Christianity (Philadelphia: University of Pennsylvania, 1981), 145; cited in Scott Hahn, A Father Who Keeps His Promises (Ann Arbor: Servant, 1998), 291-292 n. 4.
 Hahn, A Father, 233.