Obadiah
Well-known member
And when He had taken some bread and given thanks, He broke it and gave it to them, saying, “This is My body which is given for you; do this in remembrance of Me.” And in the same way He took the cup after they had eaten, saying, “This cup which is poured out for you is the new covenant in My blood.” (Luke 22:19-20)Jesus' blood (the blood of the New Covenant) had not yet been shed at the Last Supper. So the New Covenant which was sealed with His blood could not have started then. The cup at the Last Supper was foreshadowing of what was to come at the earliest the next day.
If by believing you mean a genuine, action causing, obedient faith (as the Greek word pistis denotes), then you are correct, because that faith will include repentance (Acts 3:19), confession of Jesus as Lord (Rom 10:9-10), and baptism (Mark 16:16, Acts 2:8, 1 Pet 3:21). But if you mean intellectual assent, then you are completely off base, because even the demons have that. The demons know that Jesus is God, but they either cannot or will not submit to Him and so remain condemned. Just giving intellectual assent to Jesus does not save, for He is not the savior of those who have intellectual assent, but of those who obey Him (Heb 5:9).
Generally, Christians believe that the promised New Covenant was instituted at the Last Supper as part of the Eucharist, which, in the Gospel of John, includes the New Commandment.