The belief that Judas left Jesus and the other 11 disciples before the institution of the new covenant has been the "traditional" interpretation by most Church Fathers (and conservative commentators). The following is one modern example by a conservative, Evangelical scholar:
"21. 'But look! The hand of the man who is betraying me is with me on the table.' That in all probablility what is here recorded took place before the institution of the Lord's Supper is confirmed by the following facts:
a. In the somewhat more chronologically arranged Synoptics...b. In John's parallel report concerning the exposure of the traitor, Jesus leaves the upper room immediately after Jesus told him, "What you are doing, do it faster' (John 13:21-30)..." (William Hendriksen, "The Gospel of Luke", p. 964)
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