{Till he come} (achri hou elth(8869)). Common idiom (with or
without an) with the aorist subjunctive for future time
(Robertson, _Grammar_, p. 975). In  Lu 22:18  we have he(9373) hou
elth(8869). The Lord's Supper is the great preacher (kataggellete)
of the death of Christ till his second coming ( Mt 26:29 ).