The chronology of what happened on the cross was very important as the sacrifice of the cross was the completion of the Old Covenant Passover. The one final sacrifice of the cross completing the temple sacrifice with the continuous sacrifice of the Mass. It started in the Upper Room and is completed on the cross offering pure love to the father for all times. Let us look at the chronology:
Jesus says on the cross according to St. Mark….”My God, My God, why have you forsaken me” and then according to St. John the only disciple that was there Jesus said, “I thirst”. St. John then records that Jesus then said, “It is finished”.
To understand this we have to go back to what happened at the last supper when Jesus said according to St. Mark, “I tell you the truth, I will not drink again from the fruit of the vine until that day when I drink again in the Kingdom of God.” He did not drink the last cup which is called the cup of consummation then so the Passover Seder would not be completed or consummated until the last moments on the cross when indeed His Kingdom come. This would be very odd not to complete the Passover Seder to His disciples who surely would have noticed that the obligation was not completed to the Father. It would be completed on the cross.
When Jesus said….”My God, My God, why have you forsaken me” he was not taking on the sin of the world as Protestant exegetes usually interpret but was instead giving up His humanity. It was His human nature that was forsaken and not His divine nature which was about to enter into the Kingdom or the New Covenant with mankind. He said then according to St. John….”I thirst” and then from a hyssop branch, which was the same as the branch that spread the Lamb’s blood on the door posts of the Israelites that saved their first born sons, a sponge with sour wine was put to Jesus’ lips. This was the drinking of the last cup of Passover called the cup of consummation which instituted His kingdom and the New Covenant with mankind and the end of the Old Covenant with Israel with the words, “it is finished (consummated)” meaning the Old Covenant.