Verse 15 tells us what was on Christ's mind, and again, it was not the disciples' sins. Instead, the Son of God had been fervently looking forward to this special occasion - this fellowship - with those whom the Father had given Him (see also Matthew 26:18-29; Mark 14:13-25). Like the Exodus Passover, this Passover was about eating. However, the New Testament Scriptures place the emphasis on the bread and wine. The bread and wine are not new symbols, though, but the original elements of the fellowship meal between Melchizedek and Abraham (Genesis 14:18) on the eve of a historic covenant (Genesis 15). In like manner, this Passover was a fellowship meal on the eve of the sealing of a much-anticipated covenant.
There is not time to explore this completely, but notice that Jesus says that the Passover will not be fulfilled until the Kingdom of God. It is easy to read right over that, but it is a critical part of Passover. The sin offering has already been fulfilled (Hebrews 1:3; 7:27; 9:12-14, 26-28; 10:12, 18), but the Passover has not, as it says here. This is because of Passover's theme of redemption, which is actually a process. This is why Scripture speaks of redemption in both the past (Romans 3:23-25; Ephesians 1:7; Colossians 1:14) and future tenses (Luke 21:28; Romans 8:23-25; Ephesians 1:13-14; 4:30). We have been redeemed from the death penalty, but we still need to be redeemed from this corrupted nature that incurs the death penalty (see Titus 2:11-14). God must redeem us from this flesh - this body of death, as Paul calls it - so we can fully manifest the image of our Creator. Thus, our final redemption occurs when we have been resurrected and have fully taken on the incorruptible nature (see I Corinthians 15:50). At that point, Passover will be fulfilled.
Now, Luke's account shows that Christ and the disciples drank of the cup of wine twice - once during the Passover meal, and once after. I don't know what significance this has, but it is in the biblical record, so we should at least be aware of it:
Christ's words in verses 17-18 reiterate what He declared in verse 16, that He would no longer eat of [the Passover] until it is fulfilled in the kingdom of God. The resurrected apostles will be present when Jesus resumes His partaking of the Passover meal, including the wine. So, as mentioned, Passover has forward-looking aspects.
